搅拌架每次要搅拌的时间是()min。
A.5~10
B.10~15
C.15~20
参考答案:C
噬菌体、烟草、烟草花叶病毒的核酸中具有的碱基和核苷酸的种类依次分别为[ ]
A.4种、8种、4种和4种、8种、4种
B.4种、5种、4种和4种、5种、4种
C.4种、5种、4种和4种、8种、4种
D.4种、8种、4种和4种、5种、4种
26. There was no doubt ____ it was in the supermarket _____ I lost my wallet yesterday.
A.whether, whether
B.that, that
C.that, whether
D.whether, that