题目内容
（请给出正确答案）
What happened to the crop yields since 1980？ 查看材料
A.The yields of all the crops have been declining.
B.The yield growth of some crops becomes slower.
C.The global temperatures become not so stable as before.
D.Policy and economic factors began to affect crop yields.
如果结果不匹配，请 联系老师 获取答案
更多“What happened to the crop yiel…”相关的问题
A.happened to
B.happened upon
C.occurred to
D.occurred upon
A.happened to
B.happened upon
C.occurred to
D.occurred upon
Some of what Jules described in his books ______.
A．is almost the same as what happened years later
B．is quite different from what happened years later
C．never comes true
D．seems impossible to the people today
What happened to Bob's boy, Billy？
A．He sprained an arm.
B．He injured an elbow.
C．He hurt a knee.
D．He broke a leg.
He just lied about what happened the other day.
A) brightly
B) bravely
C) blatantly
D) brilliantly
According to this passage, it is normal that ______.
A．a 1-year-old cannot recall what has happened one month ago
B．a 20-year-old can recall what happened when he was 2
C．a 20-year-old fails to recall what has happened one month ago
D．a 40-year-old has few memories for an event that happened 20 years ago
