正确答案: D

②④

题目：水可以造福人类，但水被污染后却给人类造成灾难。为了防止水的污染，下列各项：①抑制水中所有动、植物的生长；②不任意排放工业废水；③禁止使用农药和化肥；④生活污水经过净化处理后再排放。其中可以采用的方法是

解析：D

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举一反三的答案和解析：

[单选题]下列命题中，正确的是（ ）。

若a·b＝0，则a＝0，或b＝0

解析：分析：A项中a·b>0可得a、b同号，可能同为正，也可能同为负；B项中a·b<0可得a、b异号，所以错误；C项中a·b＝0可得a、b中必有一个字母的值为0，但不一定同时为零。

[单选题]29． The Browns tlunk that a small dog_________．

can help them watch their house

解析：29.B【解析】由第五段第二句、第三句可知。

[单选题]BThis is a photo (11) my family． (12) are my grandparents．Those are my (13) .This is my uncle (14) that is my aunt． This boy is my (15) ．He is my un-cle’s (16) ．(17) name is Ed． This girl (18) me．My name is Kate． I (19) twelve． I love (20) family．

of

解析：11．B  【解析】a photo of...意为“一张……的照片”。

[单选题]20．

their room

解析：20。D【解析】此处应填名词性物主代词或形容词性物主代词十名词作宾语。

[单选题]What was the date yesterday ? _____.

It was November 21st

[单选题]16．

many

[单选题]-Whenshallwegotothemuseum,thisafternoonortomorrowmorning?-_____isOK.I’mfreethesedays.

Either

[单选题]AMany children feel that the most important people in their lives are their friends．They be- lieve that their family members don-t know them as well as their friends． In large families， it is quite often for brothers and sisters to fight with each other and then they can only go to their friends for some ideas．

friends

解析：21.A【解析】从第一段前两句可知．