A. at home B. at heart

C. at will D. at sight

增加：在缺词处加一个漏字符号()，并在其下面写出该加的词。

删除：把多余的词用(＼)划掉。

修改：在错的词下画一横线，并在该词下面写出修改后的词。

注意：1. 每处错误及其修改均仅限一词；

2. 只允许修改10处，多者（从第11处起）不计分。

No body language can be attractive than smiling. Not only can a beautiful smile make us happy, but also it enables others to feel delightful. Sometimes a smile is too powerful that it gives people suffered from disasters great courage.

A little boy named Lang Zheng, for instance, impressed and encouraged a plenty of people when a serious earthquake happened in Wen Chuan. Right after he is rescued by the soldiers from the ruin, he saluted and smiled to them. Her smile was like sunshine, that warmed people who were in sadness.

It is safe to say that without smile our life would be colorless and difficult. Smile now, or you will find that life is full of wonders.

A. where B. who C. which D. when

A. what the matter was

B. what was the matter

C. what the matter is

D. what is the matter

— ____________ .

A. So did I B. Nor did I

C. So it was with me D. So I was

A. the one B. that C. one D. it

A. taking B. taken C. to take D. takes

A. It existed B. There had

C. There existed D. It had

A. which B. as C. it D. That

To many of us, the bilateral symmetry（左右对称） that characterizes the human face and the animal kingdom may be one of the first impressions we get of the world. If you reflect the left half of the face or body in a mirror, you obtain something that closely 【1】 the right half. Bilateral symmetry is so common that it could 【2】 be due to chance. If you think of the human body as a collection of some ten thousand trillion molecules, then there are countless ways to combine them into non-symmetrical shapes than into symmetrical ones. Why is it, then, that bilateral symmetry is so common? Given that all life on Earth slowly 【3】 through natural selection, the fact that we and many animals possess left-right symmetry, not, say, up-down or front-back symmetry, must have somehow 【4】 certain advantages. But how?

We can understand at least some parts of this natural “engineering” 【5】 by considering some simple physical principles. First, on the surface of the Earth, the Earth’s gravity introduces a 【6】 difference between up and down. Animals had to be able to remain stable and to cope with their weight under Earth’s perpetual downward pull. The ability to move further enhanced the difference between top and bottom.On one hand, birds had to handle the aerodynamics of flying, and on the other, be able to handle landing. Land animals had to develop some “mechanical” appendages (in other words, legs) to allow them to 【7】 themselves efficiently.

Animal locomotion was probably also 【8】 for the front-back asymmetry. Whether it was a bird, or a fish, having the sensory organs and the mouth in the front could mean the difference between finding lunch or missing it. The digestive and reproductive systems were pushed to the rear. Having eyes, ears, and noses in the front was also 【9】 for the avoidance of predators, and for the ability to explore an area before actually entering it. Life 【10】 that are fixed in one place or that move very slowly, such as trees or jellyfish, tend to have a different kind of symmetry, similar to that of a cone(球果) — they produce similar reflections in any mirror passing through their central axis.