The father and the son entered the tiger area _______ two doors were open at the time.Suddenly five tigers appeared, one of which killed the father.
---I was wondering if we could go skiing on the weekend.---good.
Only when _______ 30 years old ______ to learn English.
If the man is only interested in your looks, just shows how shallow he is.
Chinese handwriting is an important part of our culture, so young people are required to _____ handwriting.
John Snow became inspired when he thought about helping ordinary people Cholera.