当前我国邮政包裹业务资费实行的是()。 A.均一资费制  B.递进邮资制  C.交叉

交换机的计费方式包括脉冲计费和（）方式。

A.帐单计费

B.简单计费

C.详单计费

D.混合计费

如图所示的四种现象中，属于光的直线传播现象的是[ ]

A.

B.

C.

D.

男性，35岁，劳力性呼吸困难，心悸，气短，少尿，下肢浮肿1年余，1周前咽痛、咳嗽、咳黄痰后呼吸困难加重，夜间不能平卧。超声心动图示，左右心室扩张，弥漫性运动不良，左心室射血分数30%。既往无任何特殊病史。

引起上述考虑的原因是（）

A.高血压心脏病

B.心肌梗死

C.扩张型心肌病

D.心肌炎

E.甲亢性心脏病

从A、B、C三个句子中选出正确的一个。

( )1. A. My sister is ten year old.

           B. She often go to school at 7:10.

           C. What's her favorite day?

( )2. A. Math are a little boring.

           B. After lunch we play games.

           C. How much is the vegetables?

( )3. A. I think you aren't good at art.

           B. Can you play the football?

           C. How many people are there in your family?

(     )4. A. I like my English teacher best.

           B. His parents likes going to the movies.

           C. When do they go usually home?

(     )5. A. Why are you like music?

           B. School starts at 8:00 in the morning.

           C. We don't have some homework on weekends.

芒果树不宜在北方栽种，这里有多方面的原因，但起制约作用的因素是（）。

A、阳光

B、温度

C、水分