Delta acid
[化] δ酸; 2-萘酸-7-磺酸(染料中间体)
🧩 词语组成解析
delta
['deltə]
n. 希腊语字母表第四字母δ;（河流的）三角洲;[数]变量增量;
🗣️ 情景例句
But personally I believe a business letter should end with Very truly yours, not Sincerely.
还行，乔治。但是我个人相信一封商业信函应该以“敬上”结尾，而不是“谨启”。
How long is the ticket valid?
这车票有效期多久？
Indeed they can have a delightful surprise when they find something useful which they did not know they owned.
确实，一旦无意之中从自己的收藏品中找到某件有用的东西时，可以给人一种惊喜的感觉。