Section 2 Notes to difficult sentences from 1． Collecting “exotic” plants，as they are called，dates back to the earliest times．收集 “异国”植物，人们这样称呼他们，可以追溯到远古时期。句中as they are called是非限制性定语从句，as是关系代词，起连接作用，同时作从句中的主语补语。请看关系代词as的其它例句：I received the same grade as you did. Those as want to can come with me. I received the same grade as you did. Those as want to can come with me.2． However，it was not until the eighteenth and nineteenth centuries that the exploration ofthe botanical world began on a large scale．然而，直到十八、十九世纪植物学世界的探险活动才开始大规模进行。句中it was not until…that…意思是：在...以前一直(不...),...以后才。例如： It was not until he was thirty that he started to paint. 他直到三十岁才开始绘画。3． Large numbers of seeds failed to grow after long sea voyages or trips across land between Asia and Europe. 大量的种子在跨越亚洲和欧洲之后没能成功地生长。句中large number of 量词用法，它是放在名词前面并修饰名词的字。它们告诉我们「多少」(how many or how much)。例如：many trees， a few trees， few trees， several trees， a couple of trees， none of the trees。 下列量词用于不可数名词： not much dancing， a little dancing， little dancing， a bit of dancing，a good deal of dancing， a great deal of dancing， no dancing。 列量词用于可数名词和不可数名词：all of the trees/dancing， some trees/dancing，most of the trees/dancing， enough trees/dancing， a lot of trees/dancing， lots of trees/dancing，plenty of trees/dancing， a lack of trees/dancing4． Ward shipped two cases of British plants to Sydney，Australia．沃得把英国植物装船运送到澳洲悉尼。句中的shipped原来是名词，转化为动词了。 相当多名词可以用作动词。例如：Have you booked your ticket? 你的票订好了吗？ Who chaired the meeti...
