①草履虫②蜈蚣③河蚌④青蛙⑤蜘蛛⑥鲫鱼⑦乌龟⑧蚊子．
A：①②③⑤⑧
B：②③⑤⑧
C：①②③④⑤⑧
D：①②⑤⑧
在括号里填上合 适的词语。
____的语言 ____的学生
____的大雁 ____的蝌蚪
____的化石 ____的蚂蚁
When she knew her son was out of danger, she was relaxed.
It is _______ difficult work that he isn't able to do it _______.
小明使用显微镜时，看不到白亮视野．分析其原因不正确的是（ ）
