They are often happy to hear the bell ring这句话是什么时态?为什么又有are又

They are often happy to hear the bell ring这句话是什么时态?为什么又有are又 they are often h____ to hear the ball ring They are happy to hear the news.to hear the news是什么成分 1.He awoke to the ringing of an electric bell.这句话中的 ring为什么用 .He awoke to the ringing of an electric bell.这句话中的 ring为什么用r They are a happy family.They often go to the park to play to how happy i was to hear that!为什么hear用原型,这是什么时态? They are so happy to hear this ( )news They are so happy that they feel sorry when the bell rings a 那They are going to Japan the after tomorrow.的同义句又是什么? Hurry up,don;t you hear the bell _______(ring)? They are to have for lunch.这句话对吗?为什么?