The trouble is that not many students really know how to make use of their () time to its best

单项选择题One reason for the successes of Asian immigrants in the U.S. is that they have taken great() to educate their children.

A. efforts
B. pains
C. attempts
D. endeavours

单项选择题He tried very hard to （） the authorities of his capabilities and loyalty, only to find that the more he tried, the less they believed him.

A. tell
B. show
C. convince
D. encourage