turn 加to do or doing?

接动词的情况，turn to作"变成"，"转向(原来在做另外一件事）"讲，例如：
He is turning to be strong.他正在变强壮。
He turned to keep silent when he saw me.他看到我就安静了下来。

接名词的情况较为常见，意思可能是：求助于，致力于
The more depressed he got, the more he turned to drink.他越郁闷就越喝酒消愁。
The child turned to his mother for comfort. 孩子向母亲寻求安慰.
又例:
1. It turned out to be a very sad news.
2. He turned to avoid being found by others.
两句中turn to中的to都用来表示动词不定式.

turn to do

turn to do变成,打开