中性点经电阻接地电网可将接地时的异常过电压抑制在运行相电压的( )。 A．2.8倍 发布时间：2017-12-29 03:52 │ 来源：www.tikuol.com 题型：单项选择题 问题： 中性点经电阻接地电网可将接地时的异常过电压抑制在运行相电压的( )。A．2.8倍以下 B．2.5倍以下 C．2.0倍以下 D．1.8倍以下
题型：单项选择题 完形填空。 Recently, how teachers should criticize (批评) students __1__ reported in the news. It is because of a new __2__ from the Ministry of Education. It says that the head teachers have rights to criticize their students "in a proper way". Many teachers welcome the rule. They say the move will help teachers __3__ educate students. "Today's teachers are afraid it will hurt students' pride," said Ms Yang, "Most of the students are single children, and their __4__ are very protective." Yang once criticized two boy students who had fought in her class. __5__ next day, the boys' parents went to the headmaster and said that Yang had been too hard on their boys. Since then, she has been very careful __6__ criticizing students. But some teachers think the rule is too general (宽泛的). What is a "proper manner"? They ask. Here is __7__ students have to say. Wen Wen is a Junior 2 student __8__ Changsha. She says that when her teachers criticize students, they do not use harsh (刺耳的) words. Most of her classmates __9__ this kind of criticism. Guo Xiaoyu, a __10__ Beijing student thinks it is better to criticize a student in private (私下)."I don't like teachers criticizing me in front of the whole class. I lose face," she said.( ) 1. A.have been ( ) 2. A.idea ( ) 3. A.well ( ) 4. A.parents ( ) 5．A．A ( ) 6. A.with ( ) 7. A.that ( ) 8. A．in ( ) 9. A.like ( ) 10.A.15 years old B. has been B. plan B. good B. teachers B．The B. to B. when B．at B. accept B. 15-year-old C. have C. rule C. better C. friends C．／ C. for C. what C．on C. mind C. 15 year old D. was D. reason D. easier D. classmates D．One D. about D. how D．of D. reply D.15-years-old 查看答案
题型：单项选择题 已知函数f（x）=lnx，g(x)=12x2，（I）设函数F（x）=ag（x）-f（x）（a＞0），若F（x）没有零点，求a的取值范围；（II）若x1＞x2＞0，总有m[g（x1）-g（x2）]＞x1f（x1）-x2f（x2）成立，求实数m的取值范围． 查看答案