Delta ray
[电] σ射线
🧩 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;
ray
[rei]
n. （热或其他能量的）射线;光束，光线;微量;伞形花序柄;
vt. 放射;照射;（思想，希望等）闪现;发光;
🗣️ 情景例句
I have a tourist visa.
旅游签证。
What year is this?
今年是哪一年？
We need three times as much as we originally ordered.
原来的三倍。