对烘丝筒内热风特性的描述，不正确的是（）A、热风可带走筒内废气 B、进入筒内热风量可控

关于小肝癌，说法错误的是（）。

A.瘤体直径≤4cm者为小肝癌

B.圆球状或类圆球状

C.周围绕以较窄的弱回声晕

D.后方回声轻度增强

E.可呈低回声、等回声或高回声型

词语替换， 选择与句中划线部分意思相同或相近的词或短语。

1. We all know that his father is able to swim well.

A. must

B. shall

C. can

D. may

2. The old man had to stop his work because of his poor health.

A. give up

B. put up

C. look up

D. turn up

3. He was the second in the long jump at the 2004 Athens Olympics.

A. got the bronze medal

B. got the silver medal

C. got the iron medal

D. got the gold medal

4. We should try our best to study English.

A. do our best

B. do one's best

C. have a try

D. do well in

5. Class was over and the students came out of the classroom one after another.

A. up and down

B. here and there

C. by and by

D. one by one

CCRM系统数据机构共分六级。（）

化工生产上通常将石膏（CaSO₄）转化为硫酸钾肥料和氯化钙，无论从经济效益、资源综合利用还是从环境保护角度看都具有重要意义。以下是该转化的流程图。

回答下列问题：

（1）写出反应①的化学方程式                                     。

（2）过滤I操作所得固体中，出CaSO₄外还含有            （填化学式）等物质。

（3）过滤I操作所得滤液是溶液(NH₄)₂SO₄。检验滤液中是否还含有CO₃^2—的方法是            。

（4）已知不同温度下K₂SO₄的溶解度如下表：

60℃时K₂SO₄的饱和溶液591g冷却到0℃，可析出K₂SO₄固体            g。

因特网中的协议应该满足规定的层次关系，下面的选项中能正确表示协议层次和对应关系的是（）。

A.

B.

C.

D.