按照承痕体表面变化情况分类,足迹分为()、()两大类。
参考答案:立体足迹、平面足迹
Mr. Green showed his students some photos ________ at World Expo 2010 Shanghai.
A.being taken
B.taken
C.to be taken
D.having taken
— A new baby came to the earth ______ a sunny winter morning.
— How nice.
A.in
B.on
C.of
D.at