下列叙述正确的是（ ） A．SO2具有还原性，故可作漂白剂 B．Na的金属活性比

An unhappy childhood may have some negative effects on a person's character; however, they are not

always _____. [ ]

A. practical

B. avoidable

C. permanent

D. beneficial

Because he didn't finish the work on time and was fired by the company, he was very ______ about it. [ ]

A. upset

B. worrying

C. anxious

D. nervous

本月王先生的应纳税额为( )元。

A．400

B．460

C．625

D．705

简述肿块穿刺活检的步骤。

简述军事劳动时人心率限值。