Five years ago Edward decided to leave the North and____a less oppressive life in HouMon.
A. search
B. explore
C. survey
D. seek
The piston cooling system may employ similar components, except that _____ is used instead
A. a sump tank
B. a feed well
C. a double bottom tank
D. a drain tank
在相同条件下，a L氢气和b L氨气所含原子数相同，则a与b之比为（）。
A. 1:1
B. 2:1
C. 1:2
D. 1:3
先天性不育中牛白犊病是指()
A. 谬勒氏管发育不全
B. 子宫颈发育异常
C. 卵巢发育不全
D. 异性孪生母犊不育
E. 染色体异常
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