某天气系统的气流由四周向中心逆时针方向辐合,该天气系统是[ ]
A.北半球气旋
B.北半球反气旋
C.南半球气旋
D.南半球反气旋
答案:A
用所给词的适当形式填空。
1. I have a________busy week. (real)
2. Thanks for your________to the party next week. (invite)
3. Today is Tom's________birthday. (fourteen)
4. My________brother is two years________than me. (old)
试论述过渡时期总路线反映了历史的必然性。