Null check
[计] 零检验
🧩 词语组成解析
check
[tʃɛk]
vt. 检查，核对;制止，抑制;在…上打勾;
vi. 核实，查核;中止;打勾;[象棋]将一军;
n. <美>支票;制止，抑制;检验，核对;
🗣️ 情景例句
I'm exhausted. I had to work until 2 o'clock this morning.
我累死了。我一直得干到今天早上2:00。
What is the hottest area in this country?
这个国家最热的区域是哪里？
The second marks the arrival of transverse vibrations which travel more slowly and arrive several minutes after the first.
然后记录下的是横向波的到达，横向波比纵向波传播得慢，在纵向波到达几分钟后才能到达。