The number of teaching staff members in this school has decreased to 700 persons.

5.（be）three times as + 形容词+ as

上升17% rise by 17percent

日产量the daily output

导致产量下降result in a diminished output

现在我们地区的粮食产量相当于1970年的3倍。

The grain production (= output)in our area now is three times as great as that of 1970.

6.There is (was) a rapid rise in …be on the rise (有了一个较快、较慢、较稳定的上升、下降)

has been sharp increase on the increase

sudden decrease on the decline

steady decline

gradual fall

slow drop

最近几年来这个地区的产量有了迅速增长。

The  output in this area has increased rapidly in the past few years.

精彩常用词汇：

significant changes 图中一些较大变化

noticeable trend 明显趋势

during the same period 在同一时期

grow/grew 增长

unequally 不相等地