单项选择题

What effects the amount of carbon-14 on earth ()

A. The lifecycle of trees
B. The number of trees
C. The intensity of solar burning
D. The quality of air.

<上一题 目录 下一题>
热门 试题

单项选择题
The author intends to tell the readers that ().

A. the United States is a wealthy country although poverty and crime exist there.
B. crime has become a serious problem in the United States, although it is said to be a prosperous one.
C. despite the fact that crimes have been increasing rapidly in the United States, it is a Country of prosperity.
D. in spite of stories about poverty and crime in the United States, it is prospering at an Increasing rate.

单项选择题
37()

A.useful
B.usefully
C.useless
D.uselessly

相关试题
  • 45()
  • 44()
  • 43()
  • 42()
  • What do we learn from the passage...