人们对这种药物的疗效存有疑问。

There are doubts about the ___effectiveness of the drug.

如果做到这一点，课程的效果无疑会得到提高。

If this is done, the ___effectiveness of the lessons will no doubt be increased.

提高员工培训的效果是管理层的优先事项。

Improving the ___effectiveness of staff training is a priority for management.