The best times to visit Shangri-la are spring and autumn ___ the temperature is at its mildest.
It is the first time that I_______to Beijing.
----Must I do well in all the subjects, Mum?----Sure, baby! As an old saying goes, knowledge is _________.
In order to protect the trees, the old man lives _________ in a _________ house, but he doesn’t fell _________.
---We could invite John and Barbara to the Friday night party.--- Yes, _______? I’ll give them a call right now.
You’d better_________ his name, address and telephone number in your notebook before you forget them.