更换和检修用电设备时，最好的安全措施是（）。A、站在凳子上操作B、切断电源C、戴橡皮

目前，我国网民规模达到3.38亿人，其中青少年网民有1.75亿人。不少未成年人上网成瘾，整日沉迷于网络游戏，荒废了学业，损害了身体，甚至走向了犯罪。据此回答下题

1．下列对网络游戏说法正确的是[ ]

①网络游戏对开发人的智力有一定好处

②网络游戏会让人上瘾，有害无益

③网络游戏可以适当地玩一玩，但绝不能沉迷其中

④网络游戏能够丰富我们的课余生活，不应加以限制

A．①③

B．③④

C．①②

D．②④

2．七年级学生张玉为了战胜网络游戏的诱惑，在家经常帮助妈妈干家务，在校积极参加班集体活动。这种战胜诱惑的方法是[ ]

A．婉言谢绝法

B．专时专用法

C．避开诱因法

D．理智控制法

关于SARS流行病学特点正确的是

A．潜伏期患者传染性较强

B．主要通过飞沫传染，接触患者不会导致感染

C．儿童老人较多发病，青壮年少见

D．病后可获得一定程度的免疫

E．发生于夏秋季

   [1] Medical research is leading American education officials to consider having high school classes start later in the morning. The research says that teenagers are more awake later at night than adults are. When staying up late at night, the teenagers have problems learning early in the morning.

[2]Researchers in the state of Rhode Island measured the amount of the hormone(荷尔蒙) melatonin(降黑素) in people's mouths at different times of the day. Melatonin causes people to feel sleepy.

[3]They found that melatonin levels rise later at night in teenagers than they do in children and adults. It remains at higher levels in teenagers later in the morning. They said this shows that teenagers have difficulty learning early in the morning. Yet most school systems in the United States begin high school classes at about seven o'clock.

[4]A few school districts have made some changes. In 1996, school officials in Edina, Minnesota, changed the start of classes from seven thirty to eight thirty. Two years later, the nearby city of Minneapolis did the same. Teachers there reported that students were no longer sleepy in class and were happier. Staying in school later in the day did not seem to be a problem for students who had jobs after school either.

[5]Health experts say that teenagers need between eight and nine hours of sleep a night. Students _________ are likely to be late for school, fail to do their homework, fall asleep in class and have trouble taking part in class discussions.

[6]Some people, however, don't support a later start time because they say that it would limit the time for practicing sports after school. However, the Minnesota schools found that this did not hurt school sports competitions.

[7]More American school districts are discussing the possibility of changing high school start times. Researchers and teenagers say that they cannot make the change quickly enough.

1  What is the best title of the passage? (Please answer within 8 words.)

2 Please fill in the blank in the fifth paragraph with proper words or phrases to complete the sentence. (Please answer within 8 words.)

3 Complete the following statement with proper words.(Please answer within 5 words)

If they go to bed very late at night, teenagers ___________ early in the morning.

4  Do you think the change is necessary? Why? (Please answer within 15 words.)

5  What does the word “this”(line 3, paragraph 6) probably refer to?（no more than 4words）

客观主义认识论的内涵是什么？

患者男性，69岁，右上缺失，健康，近中舌侧倾斜，牙槽嵴丰满，上颌散在骨尖，间距离正常

戴用义齿1周后需复诊调的原因是()

A．加强义齿固位

B．基托下沉

C．义齿咬合平衡已建立

D．义齿基托边缘位置可确定

E．患者已经可以用新义齿嚼食物