串者男，52岁，呼吸困难伴咳嗽1年余，逐渐加重，无咳嗽，轻度杵状指，HRCT示双侧中

The computer, _______ he paid ￥3,000, was once owned by his uncle.

A．which

B．for which

C．that

D．to that

Before the final examination, some students have shown（）of tension. They even have trouble in sleeping.

A.anxiety

B.marks

C.signs

D.remarks

病毒的遗传因子可包括1-300个基因。与生命有机体不同，病毒的遗传因子可能是DNA或RNA，（但不可能同时兼有！）因此DNA不是完全通用的遗传物质。

简述出版物按类集合归并的工作程序。