Backdoor
a. 秘密的
✅ 同义词
🗣️ 情景例句
Here I am.
我在这儿！
Work today,for you know not how much you may be hindered tomrrow.
今朝有事今朝做，明朝可能阻碍多。
I had a letter from my sister yesterday.
昨天我收到了姐姐的一封信，