单项选择题
The wheel is the simplest yet the most remarkable of all inventions, because there are no wheels in nature -- no living thing was ever created with wheels()
A.轮子是一切发明中最简单也是最不起眼的,因为不存在天然的轮子——没有一种生物是生来就有轮子的。 B.轮子是一切发明中最简便却最完美的,因为自然界不存在轮子——没有一种生物是生来就会用轮子的。 C.轮子是一切发明中最简单却又最了不起的发明,因为自然界不存在轮子——没有一种生物是用轮子创造出来的。 D.轮子是一切发明中最简单,然而最了不起的发明,因为没有自然的轮子——即使有也不能用轮子创造出生物来的。
单项选择题 The purpose of the writer in writing this passage is to()
单项选择题 When the writer first went to the Red Cross clinic in Beijing to donate his blood he was surprised()
单项选择题 The number of voluntary blood donors in Beijing in 1993 is ().