The word “flip” (ParA.2) most probably means“ ______ ”.
A.decline
B.intensify
C.fluctuate
D.reverse

A.2)
B.
A.decline
B.intensify
C.fluctuate

【参考答案】

D
解析：可从文中的“Although the strength of the magnetic field v......

(↓↓↓ 点击下方‘点击查看答案’看完整答案 ↓↓↓)