室外篮、排、网球应以（）
A、土质为宜
B、草皮为宜
C、水泥为宜
参考答案：A
— Did you know any Chinese before you arrived in Beijing?
— Never ________ it, actually.
A．had I learned
B．have I learned
C．I have learned
D．I had learned
两个字符串相等的条件是 (60) 。
A．两串的长度相等B．两串包含的字符相同C．两串的长度相等，并且两串包含的字符相同D．两串的长度相等，并且对应位置上的字符相同
