如果变压器油色变暗,说明油质()。
参考答案:变酸
a比b少c,列成式子是a-c=b或b-a=c.______.(判断对错)
Look at _______ skirt, I bought it for Mum on Mother's Day. Isn't it nice? [ ]
A. a
B. an
C. the
D. 不填