Back focal length
[计] 后焦距
🧩 词语组成解析
back
[bæk]
n. 背，背部;背面，反面;后面，后部;（椅子等的）靠背;
vt. 使后退;支持;加背书于;下赌注于;
vi. 后退;倒退;
adj. 背部的;后面的;以前的;拖欠的;
adv. 以前;向后地;
focal
['fəukəl]
adj. 焦点的，有焦点的;集中在点上的;病灶的，病灶性的;
🗣️ 情景例句
Will you be so kind as to help me out of the difficulty?
帮助我克服困难，好吗？
I've changed my mind.
我已经改变主意。
He waited until the volcano became quiet and he was able to return two days later.
他等到火山平静下来，两天以后又返回去。