若a2=25,|b|=3,则a+b等于[ ]
A.-8
B.±8
C.±2
D.±8或±2
答案:D
Can you think of a situation ______people communicate only by meansof bodylanguage?
Can you think of a situation ______people communicate only by means
of
body
language?
A.that
B.which
C.where
D.when
液压系统缸体磨损严重时可采用()修复。
A.铅焊
B.焊接
C.研磨