Jack is very funny. He always makes us .[ ]
A.laugh
B.laughing
C.to laugh
D.laughs
答案:A
已知三角形ABC,求作圆经过A及AB中点M,并与BC直线相切,已知:M为△ABC的AB的中点,求证:一个经过A、M两点且与BC直线相切的圆.
全球陆地共分七大洲,即__________、__________、__________、__________、_________、______
_____和_________。