下面对胸部CT扫描技术叙述错误的是（） A.患者仰卧、头先进 B.有时为了区别少量胸

若2cosβ-1=0，则锐角β的度数为 ．

城市垃圾卫生填埋厂的HDPE渗沥液收集管（带孔，又称花管）道连接采用（）方式。

A.法兰连接

B.热熔焊接

C.承插口连接

D.胶圈连接

职业性膀胱癌的强致癌因子是（）

A.矿物油

B.沥青

C.多环芳烃

D.β-萘胺

E.苯胺

起重作业中，除了( )外均可用地锚来固定。

A．拖拉绳
B．缆风绳
C．动滑轮
D．卷扬机

Passage Two

Which of the following statements is true of what you’ve heard

A．The speaker’s father set out to round up their cattle.

B．The speaker did not dare to chase the cow there any more.

C．The speaker’s horse died in three days.

D．The cow was found dead down the valley days later.