下列等式中正确的个数是
①a5+a5=a10 ②(-a)6·(-a)3·a=a10 ③-a4·(-a)5=a20 ④25+25=26[ ]
A.0个
B.1个
C.2个
D.3个
答案:B
Unfortunately, George cannot be with us today so I am pleased to accept this award____ him. w.w.
A.in honor of
B.instead of
C.on behalf of
D.for lack of
电动机的滚动轴承温度超过100℃,称为轴承过热。