蕨类植物的植株一般苔藓植物高大的主要原因是（　　）

下列关于加速度的说法，其中正确的是（   ）

我国的宇航员将乘坐宇宙飞船遨游太空．宇航员在太空舱中可以直接对话，但在飞船外作业时，他们之间不能直接对话，必须借助电子通信设备进行交流，其原因是                                                         （   ）

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏字符号（ $\wedge$ ），并在其下面写出该加的词。

删除：把多余的词用斜线（＼）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。

    Nowadays it's common for many high school student to skip (跳过) breakfast, leading to both poor school performance or damage to their health.

    When asked why they skip the breakfast, some students say he think of breakfast as the least important meal of the day, and think it unnecessary, while others said they have too few time in the morning to have breakfast. And a third group, mostly girls who figures are their biggest concern, say they want lose weight to keep slim.

    I strongly suggest that every student has breakfast properly every day, since breakfast can provide the necessary energy one needs. In addition, having breakfast can help you concentrate in class and study efficient.