Polyphenylene
聚亚苯基
🗣️ 情景例句
Well,
好了，
What did he ask you?
他问你什么？
and by measuring the time interval between the taps and the receipt of the echoes, the depth of the sea at that point can be calculated.
测出回声间隔的时间，便可算出该处海洋的深度。