短文改错

     Recently, my classmates have had a heated discussion about if we should have optional courses

(选修课) in high schools. Some students were  in favor of optional courses. They say interest is best

teacher and  our spare time will be colorful and meaningful. Students can not only  enlarge their

knowledges but also improve their abilities.  However, others are against the idea, said that optional

courses will take up too much time as well as energy. Besides, some optional courses have something

to do with the College Entrance Examination. They are afraid they'll fall behind their classmates if they

will take optional courses. I'd like to take one or two  of the optional courses, which, I think, will certain

benefit me  lot.

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下列各组元素性质的递变情况错误的是（　　）

A．Li、Be、B原子最外层电子数依次增多

B．P、S、Cl元素最高正价依次升高

C．N、O、F电负性依次增大

D．Na、Mg、Al第一电离能逐渐增大