A：①③
B：③④
C：①②
D：①④
①5=a，②a+2=a，③a=b=4，④a=2*a
其中正确的序号是____.
—No, she isn't .
用方框中所给单词的适当形式填空，使短文通顺、正确、连贯（每个单词限用一次）。
hair, never, old, newspaper, play, but, can't, get, glasses, build
My grandfather is seventy years old, ____ he is still very healthy. He is tall and of medium ____ . He has short straight white ____ He likes reading. Every morning he ____ up very early and then reads morning ____ . When he reads, he always wears ____ . He also likes ____ chess, too. He always plays chess with his ____ friends. He ____ plays chess with me. Why? Because I ____ play chess.
51-21=____ 81-9=____ 36-24=____ 55-46=____
40-20+8=____ 86-45-20=____ 50+21+18=____
60-14-16=____ 24+45+13=____23+77-12=____
