“Where have you been?” “I’ve been to ___.”
It was not until 1911, _______ the first vitamin was identified, _______ people realized the importance of it.
We should think carefully about ______ Mr. Needham said at the meeting.
Have you ever met with this case in your life you can't understand others even if they have said something several times?
Only ____ as a translator _____ how important it is to understand foreign cultures.
Cao Cao’s tomb is reported ______ in China, which attracts nationwide attention.