Simply learn to live in the present, ________ think so much about the future or the past.

Modern forms of transportation and communication have done much to ______ the isolation（隔離）of life in Alaska.

If you don’t try your best to learn all subjects, you will ___ behind.

When I went home after work, I found my house ______ but strangely, nothing had been stolen.

The boy was very sick, but he managed to ______.

—How was your journey last week?
—Very interesting. The people there still keep the custom _____ the Ming Dynasty, which is different from other areas.

Your meaning didn’t really ______, John. I didn’t ______.

—I wonder why he has been acting so strangely these days.
—Recent pressure at work may     his behavior.

It was not rare(稀少) in      that people in      fifties were going to school for further study.

What will we do when all the oil in the world has          ?