blow hot and cold  飘忽不定，犹豫不决

英文解释：to vacillate in opinion

中文解释：飘忽不定，犹豫不决。
 
例句：
Mary blow hot and cold about her job; every day she changed her mind.
玛丽对于工作的事情拿不定主意，她今天想这样，明天又想那样。

Some people can make up their minds right away,but others blow hot and cold.
一些人能很快下决心，可另一些人就老是犹豫不决。

On the subject of marriage, he blew both hot and cold.
关于婚姻问题，他总是拿不定主意.