The professor spoke so fast during the lecture that we couldn’t _____ what he said.
It is usually warm in my hometown in March, but it be rather cold sometime.
Mary answered all the questions __________the last one, which she had never heard of before.
I've worked with children before, so I know what__________ in my new job.
Get down to the experiment right away if possible,__________ you will not finish it before dark.
---What do you think made Mary so upset? --- ______ her new bike.