The charts below show the distribution of employment in agriculture, industry and services in three countries in 1980 and the projections of distribution in 2020.

下图是1980年三国农业、工业和服务业就业分布情况，以及2020年的分布预测。

The given bar charts compare the proportions of people working in three sectors (Agriculture, Industry, and Services) in three countries in 1980, along with predicted changes in 2020.

Overall, it can be seen that services were the main source of employment for people in countries A and C, while agriculture was the main area of employment in country B. Additionally, despite some slight variations, there are no predicted changes in the overall trends of these countries’ employment distribution.

In 1980, the main source of jobs in countries A and C was services, at approximately 45% and 65%, followed by industry, at 30% and 35% respectively. Jobs in agriculture accounted for the smallest percentage of the workforce in both countries, at around 20% and 5% respectively. Both countries are expected to see a decrease in industry-related jobs and a rise in service jobs by 2020.

Country B, on the other hand, saw the largest percentage of jobs in agriculture, at approximately 70%, followed by services and industry, at approximately 35% and 20% respectively. It is predicted that trends will also remain the same in country B, with an approximate 15% decrease in agriculture jobs.

给出的柱状图比较了1980年三个国家在三个部门（农业、工业和服务业）工作的人的比例，以及2020年的预测变化。

总的来说，可以看出，服务业是A国和C国人们就业的主要来源，而农业是B国的主要就业领域。此外，尽管有一些细微的变化，这些国家的就业分布的总体趋势没有预测的变化。

1980年，A国和C国的主要工作来源是服务业，大约占45%和65%，其次是工业，分别占30%和35%。农业工作占这两个国家劳动力的比例最小，分别约为20%和5%。预计到2020年，这两个国家的工业相关工作将减少，而服务业工作将增加。

另一方面，国家B的农业工作比例最大，约为70%，其次是服务业和工业，分别约为35%和20%。据预测，B国的趋势也将保持不变，农业工作将减少约15%。