Half the class won't come.

一半的同学不会来。

If they have it today, half the class won't come.

如果他们今天举办，半个班级不会来。

A problem in thermodynamics that stymied half the class.

花费了半节课时间才解决的一个热力学问题

The ruggedness of his exams caused half the class to fail.

他的测验的难度使班上半数学生都没有通过.

More than half the class bunked off last week when there was a test.

上周测验时,这个班有半数以上的学生逃学.