Trees are useful to man mainly in three ways, the most important of which is that they can protect ______ from droughts (干旱) and floods.
The workers ___ busily when the boss came to look for something she ___ in the office.
Her brother___ while he ___ his big horse and had his leg broken.
“There is something wrong with my bike.” “It doesn't matter. I ___ lend you mine.”
“You ___ to think for youself , you are to carry out my orders.”
“Do you have any clothes ___ today, Master?” asked the servant politely.