A:
B:
C:
D:
下列关于各种酶作用的叙述,不正确的是 ( )
两个数都是质数,这两个数一定是互质数.
句子配对。
①How heavy is Tom?____ A. There are 15.
②How old is he?____B. He is 15years old.
③How much is the robot?____C. He weighs 51kg.
④How many boys are there under the tree?____D. It's September 15th.
⑤When is your birthday?____E. It's ¥15.
用N15标记的一个DNA分子放在含有N14的培养基中复制三次,则含有N15的DNA分子占全部DNA分子的比例与含有N15的DNA单链占全部DNA单链的比例分别为( )