use up:  Someone has used up all my disks. (To finish the whole of something)

vouch for:  His proposers vouched for his honesty and capability. (To give personal guarantee of the truth or accuracy of something)

wait around:  A group of stargazers waited around for the sky to clear; instead, black clouds spread across the sky. (To idle somewhere while waiting for someone or something to happen)

wait behind:  We waited behind to help clean up after the farewell party broke up. (To remain somewhere after other people have left)  

wait for:  They waited in vain for the rain to stop. (To look forward to something)

wait for:  The fans waited all morning at the airport for the television star to arrive. (To look forward to someone)

wait on:  She waits on customers with utmost courtesy and patience. (To serve food and drink at a place (e.g. restaurant) where people pay to eat and/or drink)

wait out:  We had drinks and light meals at a café while waiting out the stormy weather. (To wait for something to end) 
wait up:  Sean waits up for her every night. (To stay up while expecting someone or something to happen)

wash away:  The police believed the blood stains were washed away by the murderer. (To remove by using water) 

wash down:  I don’t need a lot of water to wash these two tiny pills down. (To make something easier to swallow by drinking water)

wash down:  The two of  us washed down the spiral staircase this morning. (To wash something with water from top to bottom)

wash off:  These stubborn dark stains will not wash off. (To remove something from a surface by cleaning with water)

wash out:  The match was completely washed out by the unexpected weather. (To cause an event to be cancelled or interrupted because of rain)

wash out:  I used the new detergent, but the curry stain wouldn’t wash out . (To remove by washing) 

wash up:  As we are in a hurry to go, let’s help her wash up the dishes. (To wash after a meal the items used in serving and eating of the meal)

wash up:  The children were told to wash up before they sat down for dinner. (To wash one’s hands and face)
wash up:  This is not the first time that a carcass of a whale is washed up the beach. (To bring something up on to the shore)

watch for:  Watch for the sign that points down to the lane leading to the waterfall. (To look out for something) 

watch out for:  While there, you had better watch out for pickpocket.  (To be careful of something)

watch over:  The woman is watching over her very sick husband in the ward. (To guard or take care of someone or something) 

work against:  Your inability to speak well is likely to work against you when you enter politics. (To harm one’s chances of success)

work at:  I am not very good at writing short stories, but I am working at it. (To make great efforts to achieve something)  
work into:  You have to work the cocoa into the eggs. (To blend) 

work off:  He always uses swearing words whenever he tries to work off his anxiety. (To get rid of something by doing something else)

work off:  She took up cycling to work off her excess pounds. (To get rid of something by doing something else that is energetic or requires effort)

work on:  We spent weeks working on the defaced sculpture. (To repair or restore something)

work on:  The participants work on their stamina by doing aerobic exercises. (To improve on something)
work on:  He has been working on his dad to give him the money for a bicycle. (To persuade)

work out:  The burglars have worked out a way to sneak into the whisky warehouse. (To plan in detail)

work out:  We have to work out the cost of living in the city before we think of working there. (To calculate)
work out:  How did the repair bill work out to such a huge amount? (To amount to a total)
work out:  She works out one hour aerobics twice a week. (To do physical exercise)
work out:  The researchers still haven’t worked out what caused this new disease. (To solve something)
work out:  We hope this new business of ours will work out well successfully. (To develop in a good way)
work out:  We couldn’t work out why he reacted in that way. (To understand the reasons for someone’s behavior)
work out:  It all worked out in the end in spite of all the difficulties. (To become successful)

work up:  I certainly worked up a big appetite after a marathon jog. (To develop a physical state through an activity or effort)

work up:  Being strongly suspicious of her husband, she has worked herself up into extreme jealousy. (To rouse the strong feeling of someone)
work up to:  He hasn’t the courage to dive from the top diving board, but he is working up to it. (To gradually prepare oneself for something difficult) 

write back:  I’ve written her ten letters in the past weeks, but she has not written back. (To reply to a letter)

write down:  You don’t have a good memory, so you’d better write down whenever you need to. (To put down in writing)

write down:  The value of the machinery was significantly written down in the latest estimation. (To reduce the value, price, etc of something such as items of stock or goods)

write in:  Hundreds of viewers wrote in to complain after the show.  (To write to express an opinion or request for information)

write into:  The other party was disputing about something that was not written into the contract. (To include something in a document) 

write off:  The bank was forced to write off some of the loans when the borrowers couldn’t be found. (To fail to recover a debt and cancel it as a bad debt)

write off:  They had to write off some of the machinery after they were destroyed in the fire. (To acknowledge an asset has no value)
write off:  His car badly damaged in an accident had to be written off. (To be damaged beyond repair)   
write off:  You shouldn’t write yourself off as a good writer so quickly. (To regard someone or something as insignificant or useless)

write out:  He couldn’t speak due to a bad sore throat, so he wrote it out instead. (To express in writing)

write out:  She wrote out a cheque for a wrong amount. (To give information on a document)

write up:  Everyone of us had to write up a report on our individual findings for the meeting. (To give an account of something in writing)

yield to:  The victim’s family yielded to the kidnappers’ demand despite the huge ransom. (To submit to pressure or demands)