—Oh, my God! My English book is nowhere to be seen.
—You __________ it at home.
A. should have left B. would have left
C. must have left D. could have left
To their relief, the doctor told them that if proper _______, Betty could recover very soon.
A. treating B. treated
C. being treated D. to be treated
_______ there are many different types of food, some animals spend their lives eating only one type.
A. Since B. Unless
C. Once D. While
As the Internet has gained popularity, there has been a change in the way ______ people spend their time.
A. which B. in which
C. where D. when
—Which city is the first ________ plastic shopping bags?
—As far as I know, it is San Francisco.
A. banned B. ban
C. banning D. to ban
By the time Dave reached the small boat, a thick white fog _______ over the surface of the water.
A. spread B. has spread
C. had spread D. was spreading
