这两个短语都含有clear，但他们表达的意思截然不同。Clear在英语里是一个很活跃的单词，动词、名词、形容词和副词，它样样具有，下面我们来分别解读一下clear在这四种词性中的意思：
1.作动词：
①清理某物或某人
I had cleared my desk before I left.
离开前我已经把书桌清理干净了。
She cleared a space on the sofa for him to sit down.
她把沙发腾出一块地方好让他坐下。
Within minutes, police had cleared the area.
几分钟之内警察就把这地方的人都赶走了。
②使头脑清醒
As her mind cleared, she remembered what had happened.
当她头脑清醒时，她想起了所发生的事情。
A good walk might clear my heard.
散一下步也许能让我的头脑清醒一点。
③面部表情放松
His face suddenly cleared as understanding dawned.
他的脸色突然明朗起来，因为他似乎明白了什么。
④做准备工作
I’m trying to clear the decks before Christmas.
我正在做一些过圣诞的准备工作。
2.作形容词
①易懂的
The question wasn’t very clear.
这个问题不是很清楚。
②晴朗的，无雾的
The skies were clear and blue.
天空晴朗，一篇蔚蓝。
③税后的，问心无愧的
He makes a clear 9000 yuan per month.
他每个月的税后收入是9000元。
I had done what I could and my conscience was clear.
我已经尽力了，我问心无愧。
④不忙的
Next Saturday is clear, how about 10 o’clock?
下周六有空，10点钟如何？
④不碰到某物
The curtains should be a couple of inches clear of the floor.
窗帘应该离地面几英寸。
3.作副词
①不靠近，远离
Please stand clear of the doors.
请别站在门口。
②很远的
You can see clear to the hills.
你能够看见远处的那些山。
4.作名词
It seems that the original suspect is in the clear.
看来原来的嫌疑犯是无辜的。
熟知了clear的这些用法，我们再来看看开头那两个短语到底是什么意思呢？
All clear: a signal (often a sound) that shows that a place or situation is no longer dangerous. (表示一种信号，表示一个地方或某种情况不再危险。)
The children hid in the basement until the all-clear sounded.
孩子们藏在地下室，直到警报解除。
All clear: 平安无事
That clear? 明白了吗？
