Sugar-sweetened beverages were the leading source of liquid calories among study subjects.
在研究对象之中，加糖饮料是液体热量的主要来源。
2
You should also take some time to study the example source code and think about ways to improve it.
您还应当花些时间研究示例源代码并考虑一些增强它的方式。
3
The homework is a good source of study material for exams and both the homework and exams is a good source of study material for comprehensive final exams (if you've got one).