1.
It is difficult to have a sensible discussion with my mother because she's always flying off at a tangent and talking about something else.
同我母亲进行有成效的讨论很困难，因为她总是突然离开话题，扯到其它一些事情上去。
2.
fly off on a tangent
ph.1. 突然离题
3.
To leave abruptly or hurriedly.
突然离开突然或匆忙地离开
4.
Then, abruptly, he stopped and, without a word, left the room.
突然，他停了下来，一句话没说就离开了房间。
5.
a lawyer should be skilled in the art of reasoning; it will not do in arguing a case to go off at a tangent into outside matters
律师要善于讲道理，辩论案件时突然离开本题说些不相干的话是不行的。
6.
He struck into another subject.
他突然转入另一个话题。
7.
separate or cause to separate abruptly.
分开或者突然造成分离。
8.
Break away
突然离开，强行逃脱
9.
He left the party without notice last night.
他昨晚突然离开舞会。
10.
The secretary abruptly left the conference room.
书记突然离开了会议室。
11.
leave suddenly and as if in a hurry.
突然离开并且好像匆忙。
12.
He was seized with deep remorse [terror].
他突然想离开这个地方。
13.
I was about to go out when it began to rain.
我正要离开的时候，突然开始下雨了。
14.
pass abruptly from one state or topic to another.
从一个状态或话题突然转向另一个。
15.
He nipped in with a smart question.
他突然插话，提出一个机智的问题。
16.
The topic veered round to the world situation.
话题突然转变到世界局势。
17.
Mystery Accident Victim Regains Power of Speech after Six Years
巴西男子六年失语最近突然开口说话
18.
suddenly leave sb/a place;escape from sb/a place
突然离开某人[某处];从某人处[某处]逃走