高中英语第一册Unit17课件
10. 以 –s 结尾的表学科的名词，如：physics; politics; mathematics; classics; informatics 等作主语时，谓语用单数。而两对称部分构成物体的名词如：compasses; glasses; scissors; flares (喇叭裤)等作主语时，谓语用复数。但如果这类名词前用了 a pair of 等，则往往用作单数。
Mathematics is well taught in our school.
The scissors are dull, but they are my only pair.
Here is a pair of shears (大剪刀).
Here are some new pairs of shoes.