Recently a debate about ______is real beauty has been raised. People are pushed to think some questions like ______ is better,artificial beauty or natural one.

Whose shirt is this? — It _______ be Li Lei’s. It is too big for him.

.－Who taught _____ to swim?－I learned it by _____.

He hasn’t heard from his friend ______ last month. [ ]

Have you ever been to Shanghai, Mary?—Yes. I ______ there for three days with my parents last year.