—Li Ping went to Australia to study and travel last year.—Yes, I know. He told me he would never forget his meaningful         there.

There are millions of websites on the Internet and there_______ a lot of useful _______on the websites.

We could hear the frightened people's _____ in the accident.

Can you offer me        ?

 I listened to Professor Chen-Ning Franklin Yang’s lecture about his study and physics, but I failed to get its key ______ .