通常情况下，微粒A和B为分子，C和E为阳离子，D为阴离子，它们都含有10个电子；

请你给校长写一封推荐信，推荐Mark当班长。信中要对Mark进行全面介绍。词数：80词左右。

1.有许多个人优点：自信，能注意每个细节，勤奋、好学；

2.乐于助人，常为我们讲解难题；

3.为人善良，不自私；

4.聪明、富于创意和想象力。

AustinFlint杂音见于（）。

A.中、重度主动脉瓣关闭不全

B.风湿性心瓣膜病的二尖瓣狭窄

C.室间隔缺损

D.二尖瓣狭窄伴明显肺动脉高压

E.二尖瓣关闭不全

阅读理解

     Many kids turn up their noses at the thought of eating fish because, well, it can smell "fishy". While it

is usually a healthy source of protein in the diet, there may be several reasons to avoid biting into a forkful

of fish. Before you break out the tartar sauce, learn some facts about fish to keep yourself and the

environment healthy.

     Some fish may contain harmful chemicals, which can be the result of both natural causes and water

pollution. Mercury is a poisonous chemical, which occurs naturally in oceans and the Earth's crust, but

also comes from manmade sources, such as pesticides, burning garbage, and the releasing of fossil fuels.

     Polychlorinated biphenyls (PCBs), a group of chemicals, can also be found in some fish. These

dangerous manmade chemicals were used in many industries until 1977, when they were banned. PCBs

were released or leaked into the air and water and have been transported around the globe.

    How do mercury and PCBs end up in fish and the food supply? When they are released into the air,

they attach themselves to particles. These particles settle on the ground and in the water and are

eventually eaten by microscopic organisms. Small fish eat the microorganisms, and large fish eat the small

fish and on up the food chain.

     Because they can negatively affect your health, the U. S. Environmental Protection Agency advises

that kids younger than 15 years old avoid fish that contain high levels of mercury and PCBs. These

include shark, swordfish, king mackerel, and tilefish.

     There are also many types of fish that are good for you, but because of overfishing are in danger of

being wiped out. Some are being fished in the wild so much that they cannot reproduce fast enough to

survive. Others are being farmed in ways that are not environmentally friendly. These fish include red

snapper, Atlantic salmon, blue fin tuna, and king crab.

     Despite these problems, there are several fish that are both healthy and sustainable, such as Alaskan

salmon, American catfish, Pacific cod, and several farmraised fish and shellfish.

【文章大意】 鱼虽富含蛋白质, 但本文却建议小孩子不要吃鱼以及说明了其中的原因.

1. How do mercury and PCBs come to our food supply?

A. Mercury and PCBs-water-fish-particles-food supply

B. Mercury and PCBs-particles-organisms-fish-food supply

C. Mercury and PCBs-particles-fish-organisms-food supply

D. Mercury and PCBs-organisms-ground and water-fish-food supply

2. The underlined word "they" (Paragraph 5) refers to "________".

A. fish  

B. particles

C. microscopic organisms  

D. mercury and PCBs

3. According to the passage, which group of fish can be safely eaten by young kids?

A. Shellfish；tilefish；Alaskan salmon.

B. King crab；king mackerel；Pacific cod.

C. Pacific cod；Alaskan salmon；American catfish.

D. Pacific cod；Atlantic salmon；swordfish.

4. The writer is most likely to agree that ________.

A. we should be careful when deciding what kind of fish to eat

B. overfishing is the main cause of fish poisoning

C. most types of fish can be safely raised on fish farms

D. the government should ban children under 15 from eating fish

5. It can be inferred from the passage that ________.

A. children like eating fish because it smells fishy

B. if you want to be more environmentally friendly, eat less fish

C. PCBs were not allowed to be used in food industry before 1977

D. adults might be less affected by high chemical levels in fish

开、关滚翻式货舱盖的动力设备是：（）

A.舱口液压开关

B.起货绞车或克令吊

C.专用绞车

D.液压转动装置

按照沟通的含义及要素，具体来说它有以下几方面的特点（）

A、信息的传递

B、信息的理解

C、双方的传播、交换和说服

D、是一个双向互动的历程