如果2是一元二次方程x2=x+c的一个根,那么常数c是 [ ]
A.2
B.-2
C.4
D.-4
答案:A
Not until he took off his sunglasses _______ him.
A.I recognized
B.I did recognize
C.did I recognize
D.do I recognize
汉译英:“投保人”,正确的翻译为()。
A.policyholder
B.premium
C.insured
D.insurant