请你叫他尽快给我回电话好吗？（call sb back=ting sb back)
我们学习语言是为了交流思想(communicate)
人们发现多吃水果是必要的(find it necessary to)
我骑车上学只需20分钟(it takes...to....)
她打算给她学校校长发一个电子信函(e-mail)
she thought it unnecessary to argue with him about it
please be sure to confirm your return flight two days in advance
if you want to return this camera,you must bring your receipt
l like to make friends with those who are ready to help others
lt's very kind of you to come to the railway station to see me off