So difficult __________ it to work out the problem that I decided to ask Tom for advice.
_________ in the leg made it impossible for him to walk home.
I used to drink a lot of tea but these days I _________ coffee. A. prefer B. preferred C. have preferred D. am preferring
–What should I do first? --The instructions _________ that you should mix flour with water carefully first.
Pleasant music is often played _________ classes to make students refreshed and relaxed for a while.
二、单项选择Don’t worry too much about ________ mistakes. They’re ________ natural part of learning something.