随着讨论的深入，他们的意见分歧越来越大。

As the discussion went on, their differences of opinion ___widened.

医生建议她多做眼部运动来扩大视野范围。

The doctor advised her to do eye exercises to ___widen her field of vision.

这项研究最初只关注儿童，后来扩大到包括成年人。

The study initially focused on children but later ___widened to include adults.