病毒是一类结构非常简单的生物，他们没有细胞结构，一般是由____ 和内部____ 构成。

增加：在缺词处加一个漏词符号(∧)，并在其下面写出该加的词。

删除：把多余的词用线(＼)划掉。

修改：在错的词同下划一横线，并在该词下面写出修改后的词。

注意：每处错误及其修改均限一词。只允许修改10处，多者(从第11处起)不计分。

    The summer job is very much popular among some university students. Long before the end of a school year, students start their summer vacation job search. They send letters to businesses, going to job interviews, and ask our friends and relations for help. By June the students usually had found jobs and then they begin preparing enter the world of work.

    Reasons for wanting a summer job differs from student to student. Some students work to pay their school expenses, some work to gain experience or just to fun. Salesmen or waiters are two of the most common job that students try to find.

下列句子中的“故”字，与其它意义不同的一项是(　　)

青海省西北部的____ 盆地，矿藏丰富，被人们称为____ 。东部____ 区有盐盖，____ 盐湖附近建起了我国最大的____ 。