The most interesting thing () Americans is that they are brought up to believe they are the best at everything.

单项选择题Each () effort a baby makes at speech is a sign of intellectual development.

A. cordial
B. compact
C. clumsy
D. chronic

单项选择题China moved to ()its grain production when its grain output had kept declining for five consecutive years.

A. turn up
B. take up
C. step up
D. make up