Ifdef
n. 如果定义了
🗣️ 情景例句
Ooh, speaking of keeping busy-I have an early start tomorrow,and the baby-sitter has to get home.
哦， 说到忙于工作，我明天还得早起，而且临时保姆也该回家了。
Liberty often degenerates into lawlessness.
自由随便，经常堕落到无法无天。
It has belonged to our family for a long time.
我们家有这件乐器已经很久了，