噬菌体外壳的合成场所是（）
A.细菌的核糖体
B.噬菌体的核糖体
C.噬菌体基质
D.细菌的核区
参考答案：A
John’s father was too old to run the company, so John ______ the company after leaving university.[ ]
A. took on
B. took over
C. took up
D. took in
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