Wavefront
[计] 波前
🗣️ 情景例句
What number are you at?
你的电话号码是什么？
Where were you yesterday afternoon?
你昨天下午在哪儿？
There is only enough spring water to supply the needs of the houses, so we have to pump from the river for farm use.
泉水只能满足家庭生活用水，因此我们必须从河里抽水以用于农业生产。