Fact: Benjamin Franklin invented bifocals.

小常识：本杰明·富兰克林发明了近视和远视眼镜。

Nowadays, these glasses are known as bifocals .

如今，这被称为双光眼镜。

Take care when stepping on and off the escalator; take extra care if you wear bifocals.

在上下扶梯的时候一定要留神，尤其是当你还戴着眼镜的时候。

Take care when stepping on and off the escalator ; take extra care if you wear bifocals .

在上下扶梯的时候一定要留神，尤其是当你还戴着眼镜的时候。

Where they confront the startled PROJECTIONIST, an old con blinking at them through thick bifocals.

放映室里他们碰到目瞪口呆的放映员--一个老囚犯，透过厚厚的眼睛片惊愕的看着他们。

Occasionally, children who have crossed eyes may need to have bifocals to help control the crossing.

偶尔有内斜视的孩子会需要双光镜来控制内斜。