I couldn't follow the talk because he kept jumping about from one topic to another.

我听不明白他的讲话，他老是转换话题。

《牛津词典》

This is a really good topic to do with the class before an exam because it's a little bit of a lighter topic.

这对于考试之前的一节课来说是一个非常好的课题，因为这是一个稍微轻松一点的课题。

youdao

When I taught, I would assign a topic to children that they would write about.

教书时，我会给孩子们布置个写作题。

《柯林斯英汉双解大词典》

"Safety and security of our volunteers is absolutely our top priority and we are continually looking at this topic and I have to say that in the last few years we have done an amazing amount of work to try to improve both our systems to support volunteers, to ensure confidentiality and to strengthen their preparedness and training."

VOA: special.2011.03.28

This is a really good topic to do the class before an exam because it's a little bit of a lighter topic.

这对于考试之前的一节课来说,是一个非常好的课题,因为这是一个稍微轻松一点的课题。

麻省理工公开课 - 化学原理课程节选

Ok, double line. If there are no questions I'm going to make a dramatic change in topic.

好的，这是重点，如果没什么问题,我要讲下面的内容。

麻省理工公开课 - 计算机科学及编程导论课程节选

Noise can be considered a non-newsworthy topic to some (like gossip) but newsworthy to others.

FORBES: Digg Digs Deep With New Moderated News Portal

In each class, the facilitator introduces a health related topic to discuss with learners.

UNESCO: Country Profile: Cambodia

The fiscal cliff will not be a new topic to regular readers of this column.

FORBES: For The Republicans There's An Opportunity At The Fiscal Cliff