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

Recently people have made great progress in using ____power of nature to produce____ electricity.

Our school motto reflects the importance we ______ to good manners, hard work and success.

I’m sorry I’ll have to ___ your present.

David, is this your sister’sbike — No, it’s not ______. It’s my brother’s.