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问题 单项选择题 A1型题

辐射所致的细胞凋亡主要经历引发性刺激、下列哪种和死亡反应三个过程（）。

A.DNA断裂

B.DNA修复

C.滞后阶段调节

D.基因表达

E.RNA复制

答案

参考答案：C

填空题



As always, I am pleased to be here at the National Press Club for my (1) Speech. This is the seventh time I have had the (2) to give this speech, and over the years I have talked about a wide range of issues: (3) , reading, setting high expectations, improving the teaching profession, and (4) the American high school -- to name just a few.
I have just returned from a five-day, (5) tour of schools in rural America. We started in Monroe, Louisiana, and finished (6) later in Paducah, Kentucky. What I noticed most about the trip was the weather. Every time I (7) my Success Express School Bus, the local people who came to greet me (8) that the record for (9) had just been broken in their community. In each place, the temperature was always between (10) degrees.
Now, I have very good people on my staff. But the next time we plan a (11) , I’m going to have a (12) on my staff. I took this bus trip through rural America to make an important point that the (13) of children in our nation’s small towns cannot be ignored. Twenty-five percent of all our school children live in (14) all over America.
When it comes to our children, let’s always remember that children everywhere have (15) and (16) . Yet, schools in small towns too often have to (17) because of limited resources and a (18) . On my trip I put a p focus on the issues that matter in rural America, with a particular emphasis on (19) schools, reducing class size, and overcoming the (20) .
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多项选择题

一个外来种的引种成功的标准⑴（）、⑵（）、⑶（）。

A、不需特殊保护措施，能正常生长，无严重病虫害

B、比引进区相边树种有较高的经济价值

C、容易大量繁殖

D、产量高
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