有关中毒型痢疾的描述中，哪项是错误的： A．多由毒力强的痢疾杆菌引起 B．肠道病变主

Many people like to have a picnic _____.[ ]

A. out doors

B. out the doors

C. outdoors

D. in outdoors

根据句意及首字母提示填空,完成下列句子。

1. B_____ Lily and Lucy are outgoing. They have lots of friends.

2. Edison showed great i_____ in science when he was a little boy.

3. Nina went to school t _____she didn't feel very well today.

4. I'm d_____ from Rick. He is a little calmer than I.

5. It's not polite (礼貌的) to l_____ at others when they make mistakes (错误).

下列关于锅炉受热面的结构布置说法不正确的是( )。

A．锅炉的辐射受热面主要指布置在炉膛内的水冷壁管
B．水冷壁由水循环回路的上升管组成
C．水冷壁布置于炉膛的中心
D．炉膛的形状和容积大小对锅炉的安全、经济运行有很大的影响

秦长城是在（）北方长城的基础上修筑起来的。

A、齐、赵、燕

B、秦、魏、赵

C、秦、赵、燕

D、楚、秦、齐

一般要求移动式油机和基站内固定式油机运行（）小时更换机油和清洗空气滤清器。

A、100

B、200

C、300

D、500