My classmate Lily is         in English because she once stayed in the U.S. for several years.

A survey says what parents say and do in daily life usually has a(n) ______ influence on their child.

Old people need special care in winter, as they are very______ to sudden change of the weather.

(2009安徽合肥质检)Having failed in many attempts，the bird       managed to escape from the cage．

The twins are so much__________that it is difficult to tell one from the other.