H-d
abbr. heavy-duty 关税重的; 重型的; high-density 高密度; 大密度
🗣️ 情景例句
She's smart and sensitive for her age.
就这样的年龄来说 ，她很聪明而且懂事。
I don't have a phonograph,either.
我也没有留声机。
Then knowledge began to be accumulated according to a systematic plan.
于是，知识便开始有系统有计划地积累起来。