下列属于PCR技术的条件的是 ①单链的脱氧核苷酸序列引物 ②目

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问题选择题

下列属于PCR技术的条件的是

①单链的脱氧核苷酸序列引物 ②目的基因所在的DNA片段 ③脱氧核苷酸 ④核糖核苷酸 ⑤DNA连接酶 ⑥DNA聚合酶 ⑦DNA限制性内切酶[ ]

A．①②③⑤

B．①②③⑥

C．①②③⑤⑦

D．①②④⑤⑦

答案

答案：B

填空题

用 join/join in/take part in/attend 的适当形式填空。

1. We're going to visit the flower show tomorrow. Will you __________us?

2.How many countries_________ the last Olympic Games?

3. He didn't _______-school yesterday because of his illness.

4. All the league members_______the meeting,at which ten students _______ the league.

5.Will you_______us_______playing basketball?

单项选择题

拔除上、下前牙断根时支点应为

A．唇侧骨板

B．腭（舌）侧骨板

C．牙槽间隔

D．牙槽骨壁

E．C+D