为什么说人工林的发展有可能造成病虫害的蔓延?

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问题:

为什么说人工林的发展有可能造成病虫害的蔓延?

考点:生态学生态学综合练习生态学综合练习题库
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已知点F(0,1),一动圆过点F且与圆x2+(y+1)2=8内切,
(1)求动圆圆心的轨迹C的方程;
(2)设点A(a,0),点P为曲线C上任一点,求点A到点P距离的最大值d(a);
(3)在0<a<1的条件下,设△POA的面积为s1(O是坐标原点,P是曲线C上横坐标为a的点),以d(a)为边长的正方形的面积为s2.若正数m满足s1
1
4
ms2
,问m是否存在最小值,若存在,请求出此最小值,若不存在,请说明理由.
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__________along the quiet road at forty miles an hour,and then an old man suddenly started to cross the road in front of me.

A.Driving

B.I was driving

C.Having driven

D.When I was driving

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There are good Santas and there are bad Santas. The good Santas all realize one thing: In the mind of a child, Santa Claus is perfect.

That’s difficult. And so they come from around the world to attend the Charles W. Howard School in Midland, Mich. The school offers a three-day, 40-hour course for Santas hoping to be excellent. There’s a real range to what Santas earn, from big bucks for large events to no pay for charities. One thing for them all is a pure love for children.

A former Macy’s Santa named Charles Howard founded the Michigan school in 1937. “Many people will think if you have a suit and you’re a Santa,” said Tom Valent, the school’s current dean. “It’s more than that.” So with a pet reindeer, his properly named wife Holly and a workshop full of wonder.

The school teaches everything from breathing techniques for carol singing to the beard maintenance. There are lessons in child psychology, sign language and even media training for talk-show appearances and call-in shows. Santas also need to make sure they know all the names of the reindeer. What’s harder to deal with, however, is children who ask for Christmas gifts like bringing daddy home or making mommy happy again.

After spending time in the classroom, Weir went to the mall to test his training. However, at one point, his hat fell off, and he was unsure how to react. “You’re the real Santa,” Valent said. “Pick that hat up, slip it back on, keep smiling and do your job. You’ve got to stay on top of your game. Even the last one at night, when you’re tired, you’ve got to remember: This one’s forever, so do a good job.”

Notes:

①    charity  n. 慈善,慈善团体

②    reindeer  n. 驯鹿

小题1:According to the passage, good Santas should be the ones that ________.

A.can offer the children some gifts

B.help adults look after their children

C.have ability to make children happy

D.should be perfect in the mind of children小题2: The underlined words “big bucks” should refer to ________.

A.lots of money

B.many gifts

C.loves for children

D.gifts from children小题3: The Michigan school was founded by Charles Howard with the purpose to ________.

A.train the pet reindeer for the Santas

B.earned money from its students

C.train perfect Santas for the world

D.show the world’s concern to the poor小题4: According to Weir’s performance, we can conclude that ________.

A.Weir was short of experience

B.Weir was not fit for the job as a Santa

C.Weir did very badly in the game

D.Weir was not a good student in school

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周老师为某大学法律系教授,今年7月份,周老师个人收入情况如下:(1)工资收入2000元;(2)出版个人学术专著一部,获稿酬5000元;(3)周教授任某股份有限公司法律顾问,取得收入8000元,从中捐给希望工程(教育)基金会4000元。周教授7月份应纳个人所得税:

A.1476元

B.1728元

C.1700元

D.1856元

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白炽灯泡离绝缘台过近,绝缘台易受热而烤焦、起火,故应在灯泡与绝缘台间设置隔热阻燃制品。

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