You’d better write down the phone number ofthat restaurant for future .

It still puzzles today’s scientists_____ some mammals produce their young _____others lay eggs to producetheir offspring (后代)[ ]

The experiment shows that proper amounts of exercise,if ______ regularly, can improve our health.

I feel __ interesting to talk with native speakers of English.

You didn’t wait for Mr. Black last night, did you——No, but we ____. He didn’t return home at all.