Question

阅读下面材料，在空白处填入适当的内容（不多于3个单词）或括号内单词的正确形式。

Discoveries about the nature of DNA in the 1940s made1. ________ possible for cloning experiments to progress. In 1944 the discovery 2.________ genetic information for each cell was kept in the cell’s DNA gave scientists new ways to attempt 3.________ (clone) animals.

The first cloned animal was a tadpole4. ________ was cloned in 1952. Thomas J. King and Robert W. Briggs believed, based on their clones, that young cells were more viable (可生长发育的) for the cloning process than adult cells.

The next successful cloning experiments also resulted 5.________ cloned frogs. John Gurdon cloned South African frogs in 1962. His experiments proved that the previous theory that adult cells were 6.________ (able) to be used in the cloning process was wrong. From 1962 to 1965, more frog clones were created from adult frog cells.

While animal cloning had been the focus of cloning experiments, the 1960s also saw7. ________ types of cloning. In 1964 F. C. Steward 8.________ (undertake) an experiment in which he took an adult cell from a carrot plant and successfully cloned the plant.

So far more than 20 different animals, 9.________ (include) dogs, cats, and the famous Dolly, have been cloned, 10. ________ human cloning research has been forbidden in many countries.

Answer

1.it

2.that

3.to clone

4.that

5.in

6.unable

7.other

8.undertook

9.including

10.but

【解析】

试题分析：本文是一篇说明文。讲的是关于克隆。

1.】it make +it +形容词+to do sth.在此句式中it/是形式宾语，后面的动词不定式是真正的宾语。故填it 。

2.that the discovery后面是其具体内容，是同位语从句，故填 that.它只起引导作用。

3.to clone attempt to do sth.企图做某事。故填to clone。

4.that The first cloned animal是先行词，指物，从句缺少主语和引导词，序数词修饰先行词，故填that。这是一个分割定语从句。

5.in 固定词组result in引起，导致。接下来成功的克隆实验也会导致克隆青蛙。故填in。

6.unable 句意：成熟的细胞不能用在克隆过程中的理论是错误的。故填unable。

7.other 句意：在20世纪60年代，我们也看到了其他种类的克隆。故填other.

8.undertook 根据In 1964可知用一般过去时态，故填undertook。

9.including 到目前为止，已有20多种动物被克隆，包括狗、猫等。故填including. Including（介词）包括，包含。

10.句意：到目前为止，已有20多种动物被克隆，包括狗、猫等，但是人类的克隆研究已经被禁止。前后是转折关系，故填but.

【知识拓展】

1.result in导致，产生结果；result from起因；as a result结果；as a result of由于---。

2.one---，the other---，（两个中的）一个---，另一个----；some---，others---，一些---，另一些；other+可数名词复数。

考点：考查语法填空