Our neighbors are warm and_____. They brought us a cake the day we moved in()
A. friendship
B. friendly
C. friend
D. unfriendly
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p®p*跃迁不能产生下列哪种吸收带()
A. E1
B. E2
C. B
D. R
I found mountain climbing quite_when I first started but now I just love it()
A. tough
B. perfect
C. terrible
D. wonderful
下列化合物中,同时有π→π, σ→σ跃迁的化合物是()
A. 甲烷
B. 碘甲烷
C. 1,3-丁二烯
D. 甲醇
所有的化学及酶促反应在MSI区间Ⅰ和区间Ⅱ的边界(aw=0.20-0.30)处,其反应速率均最低()