You cwhere the air is thin.

Was it in the village ______ he was born ________ thetalented journalist met the retired professor

Smoking, ______ is a bad habit, is popular with the young.

ne can answer the question _______ wecan complete the task in time, do you know— Yes, and this is because we don’t knowthe way _______ the scientist used last time．

下列各句中，加点的词语运用正确的一项是（ ）