Now in the market there are too many oranges, making the prices down, so I suggest _____.

Since he often travels on business, he can ______ himself to sleeping in any place he can find.

_______ the secret of nature, the young scientist haslittle time for entertainment.

I can’t remember _____ made the teacher give Mary the permission to leave the class earlier.

The pen, _______ I had been writing for ten years, was broken.