The bell rang ______ the teacher was explaining the answer to the students.

He wrote a letter ___he explained what had happened in the accident.

Have you got an iPhone 5—No, many young people began to say “No” to it becauseof _________ follow-up service. By the way, I am a supporter of Chineseproducts.

Girl students in some schools are not allowed______ long hair.

As is known to all, earthquakes are ___________ disasters _________ can destroy buildings and kill people.