Tetranitrocompound
四硝基化合物
🗣️ 情景例句
we don't have to.
我们不必勉强。
Let's begin now.
现在让我们开始。
We had spent several days in a small town and visited a number of old churches in the vicinity.
我们在一座小镇上逗留了几天，参观了附近的许多古老的教堂。