在演讲中使用数据可以增强说服力。

Using statistics in the speech ___heightened its persuasiveness.

他们加高了花坛的边缘以防泥土溢出。

They ___heightened the edges of the flower bed to prevent soil from spilling out.

紧张的气氛让他的警觉性提高了。

The tense atmosphere ___heightened his alertness.