out 意为“得出（结果、总数等）”。如：
This math problem is too difficult. I can ’ t work it out. 这道数学题太难，我算不出来。
out of 意为“用光；耗尽”。如：
It is very important that this organization does not run out of money. 这个组织没有用光钱，这是很重要的。
out 意为“出去；熄灭”。如：
What about going out for a walk ？ 出去散步怎么样？
I was doing my homework when the lights went out. 我正在做家庭作业时，灯突然灭了。
out 意为“查明；弄清”。如：
We must find out who broke the window. 我们必须查明是谁打碎了窗户。