A:
B:
C:
D:
等腰三角形的一个角为40°,则它的底角为____.
NA为阿伏加德罗常数的值,下列说法正确的是( )
如图所示电路,电源电压不变,闭合开关,当滑动变阻器R1的滑片向上移动时,以下说法正确的是( )
⑴A friend sent the CDs to me.____ A.
⑵We can find information from books.____ B.
⑶Let's go to the library.____ C.
⑷This is a book about science.____ D.
⑸I want a Chinese book.____ E.