Between 1850 and 1910 the bison population is thought to have fallen from 60 million to just a few hundred.
人们认为,在1850年到1910年之间,野牛的头数从6,000万头降到只有几百头了。
If you want to send a letter to an office abroad that is in a different time zone, you can send a fax, and it will be received even though the office is not open.
如果你要寄信到不同时区的国外办公室,你可以发个传真,即使办公室不开门,信也会被收到。
4 Think of a time when you were happiest. What were you doing?