1 . 人们发现很多濒危动物被日夜保护着。(watch over)
People found many endangered animals ________ day and night.

2 . Researchers at the University of California found that_________ (expose) to the cold increases levels of a protein _________helps form brown fat — the type of fat that produces heat and keeps us warm. （所给词的适当形式填空）

3 . 我建议坐飞机去纽约。
I ________ ________ to New York by air.

4 . Thanks for agreeing to do this interview. Would you mind________ (share) with our audience a little bit about yourself and your websites? （所给词的适当形式填空）