小烤鸭们，关于there be 句型我们上期提到了“有”的相关概念。语法的准确性和多样性是雅思写作和口语的四大评分标准之一，所谓知己知彼百战不殆，此时灵活的使用和转换句式，就显得so…oo…oo..oo important了。本期新航道雅思语法小编带你们一起去探索一下there be 句型中不可或缺的介词短语的使用。
小作文基本图形
（参考C5 Test1 Task 1）
There was an increase in the percentage of aging population in Japan, Sweden and the USA.
解析：通常 in +时间（如in 1940）/地点（国家、城市等）；当然，在没有给出描述对象的句子中，可以用in引出描述对象
There was a general upward trend in the number of elderly people in all three countries over the period from 1940 to 2020.
There was a slight rise from 8% in 1940 to 10% in 1960 in the percentage of elderly people in the USA.
解析：from …to固定搭配，常常结对出现，表示“从…到…”，体现动态变化；但若上文说过起点数据，则直接写to+终点数据即可，表示“达到某个值”。
There was a sharp increase of /by 5% in the percentage of elderly people in 1980 in the USA.
解析：of +数据，表示变化的差值；by+数据，同样也表示变化的净增量或净减量，用来体现动态变化。
In the next four decades there was a gradual decrease to around14%，and then the figure will reach the peak at almost 25% in 2040.
解析：at +数据，表示某一时间的数据，多用于静态图；表示“到达峰值”，多用于动态图。
There would be an increase in the percentage of elderly people in all three countries, with almost 25% of the respective populations by the year 2040.
解析：with+数据，表示某个时刻的数据用法同at；数据整体增加或减少，with结构进行具体说明。
总结
在there be 句型的应用中，突出趋势的变化的同时，不要忽略介词在导入数据时的重要作用，让我们尝试着练习一下吧！
Exercise：根据C15T2图表
Between 2010 and 2017，there was an substantial increase in ______visitors staying on cruise ships.
解析：the amount of +不可数名词，the percentage of 百分比，the proportion of 比例。visitor是可数名词故选择the number of
