I.               Key vocabulary to describe trends:

Verbs:

Nouns

Adverbs & Adjectives

Notes:

l  surge; soar/collapse;  plummet表示增长很快/下降很快，不需要加副词或者形容词来修饰它们。

l  Peak/reach a peak 达到高峰;  reach a plateau 保持高位； bottom out/hit the bottom 达到低谷。

II.              Verb tenses and time phrases used to describe trends

Ø  以下是一些表示趋势变化图表常用到的时间词汇以及相应的时态。

In: (e.g. In 1999/ In the 20^th century/In the first ten years, there was a significant increase in production)

For: (e.g. For the first six months/ For twenty years, the number of employees remained the same.

During:( e.g. During the first six months/ During the first half of this century/During the remainder of the year, production was slowing down, while imports increased.

From…to/until…: (e.g. From August to/until November/From 1950 to 1960, there was no change in energy use.)

Between…and…( e.g. Between August and November/Between 1950 and 1960, there was no change in energy use.)

Before/after:(e.g. Before 1960 the number remained small, but after 1965 there was a sudden increase.)

Around/about: (e.g. Around/about 1980 there was a change in the number of female part-time employees.)

By: (e.g. By the late 19^th century the rural workforce had declined significantly.

At: (e.g. At the end of the last century there was a sharp increase in manufacturing.)

Since:(e.g. Since the 19^th century there has been a steady decline.)

 Other phrases

(in ) the period from…to … (in ) the period between… and…

Over the period … to … Over the next years/decades/quarter of a century etc.

Over a ten year period    In the first/last three months of the year

Throughout the 19^th century   From that time on

After that   Then    In the 1980s

  III.                Basic sentence patterns used to describe trends:

   Ø  Basic sentence structure 1:

Ø  Basic sentence structure 2:

Ø  Other sentence structures: