植物组织培养，一般取植物的芽、茎尖或根尖的组织细胞进行培养。不属于取材理由的是(     )

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: 把多余的词用斜线(\) 划掉。

修改: 在错的词下划一横线，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。

    Mr. Johnson is a hardworking teacher. Every day, he spends too much time with his work. With little sleep and hardly any break, so he works from morning till night. Hard work have made him very ill. “He has ruined his healthy. We are worried about him.” That is which other teachers say. Yesterday afternoon. I paid visit to Mr. Johnson. I was eager to see him, but outside her room I stopped. I had to calm myself down. Quietly I step into the room. I saw him lying in bed, looking at some of the picture we had taken together. I understood that he missed us just as many as we missed him.

认识物质是为了更好地利用物质。下列变化中，与其他变化有根本区别的一种是（   ）

下列关于制作真核细胞的三维结构模型的说法，正确的是（　　）

据英国《每日电讯报》2009年12月1日报道，英国维珍银河公司建造的接载游客上太空旅行的商业宇宙飞船“太空船二号”(SpaceShipTwo)已经完工，准备在2010年初进行首次试航，此后太空船二号被正式用于开展太空旅行业务。目前已有300人预定了太空旅行舱位。另据《人民日报海外版》11月7日报道，太空旅游渐成时尚。据此回答下列题。