It's because of "A."全都因為A

because of:因為； 由于

The war was lost because of a shortage of munitions.

戰爭因軍火不足而失敗。

It's not me I'm worried about.我擔心的不是自己

worry about:擔心； 煩惱

Don't worry about little things.

別為瑣事煩惱。

we look guilty as hell.看上去就像我們是兇手

as well:也；又

Tom is very unfriendly to me as well.

湯姆對我也很不友善。

That's what you were arguing about this morning.這就是今早你跟她們吵的原因

argue about:討論(議論)

I'm not going to argue about this.

我不想爭論這個問題。

The couple begin to argue about money.

夫婦倆開始為錢爭吵。

They'll figure it out. 她們會弄清楚的

figure out:想出；解決

I can't figure out why he is absent.

我弄不明白他為什么缺席。

She couldn't figure out who put a tail on her.

她猜不透誰派人盯她的梢。