青藏高原夏季气温比长江中下游地区低很多，主要原因是（    ）

已知两曲线的参数方程分别为 和 ，它们的交点坐标为____.

读一读，选一选

____ Is your father here today?                           A. No, I don't.

____ What does your mother do?                       B. He's a businessman.

____ Do you want to be a head teacher?            C. No. He's in Australia.

____ What does he do?                                       D. She's a head teacher.