七大洲中,面积最小的是( )
A:非洲
B:大洋洲
C:北美洲
D:亚洲
已知椭圆 x2a2+y2b2=1(a>b>0) 的离心率为 63 ,焦距为 22 ,抛物线 C2:x2=2py(p>0) 的焦点F是椭圆C1的顶点.
(I)求C1与C2′的标准方程;
(II)已知直线y=kx+m与C2相切,与C1交于P,Q两点,且满足∠PFQ=90°,求k的值.
我市小华同学准备利用暑假骑车外出旅行,如果他从学校出发依次向正南、正东、正北、正西各骑100公里,那么他最后到 达的地点应该是( )
请根据所听到的内容,选择表格中的正确信息,用5—6句话进行复述。
(将复述内容写下来)。
⑴ How about studying abroad in recent years? (enjoyable/popular)
Advantages
⑵ What's the first advantage?
(make more friends/experience foreign life)
⑶ What's the second advantage?
(improve their foreign languages/learn about different cultures)
Disadvantages
⑷ What's the first disadvantage?
(too young to look after themselves/too young to learn)
⑸ What's the second disadvantage?(the low cost/the high cost)
你可以这样开始:The speaker is talking about…
Answer:____