I called you yesterday evening, but there was no answer.–Oh, I am sorry. I __________ dinner in my friend’s home.

Our teacher told us light (光) _________ much faster than sound .

David talked with a friend of ________ on the Internet for a long time yesterday.

. My uncle will come to Shanghai ______ next week .He says he will stay here for______.

You will find ______ useful to learn even a little English.