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 estimate his age to be about 30.
我估计他的年龄大约30岁。
It's hard to say.
难说。
So the number of stars that we know exist is now estimated at about 300 million million million.
因此，我们所知道的现有恒星数目估计约有30亿×1000亿颗。