起始罚分
参考答案:
用来评估一系列新空位的罚分;序列比对中空位罚分的一部分。
先化简,再求值:2(xy-xy2+3)-(-4xy2+xy-1),其中x=-4,y=-3.
What at nine o’clock last Sunday morning?
A. was you doing B. were you doing C. are they doing