不可数名词没有表示复数的“-s”标志，因此前面不可有数目字，只可以有数量词。例如我们可以说①， 不可以说②：
①There is not much furniture in the office.
②There are not many furnitures in the office.
这是不是说不可数名词就不可数呢？不然。相反的，不可数名词也是可数的，主要方法是借重单位词（unit word），如：
a piece of, a cup of, a drop of, a lump of, a handful of, a flash of, a blade of, a head of, a bar of, an ear of等。
如果数目是超过“一”，就以确实数目取代“一”。例如：
two pieces of, three cups of 和 five lumps of 等。
现在试试把上述这类单位词和适当的不可数名词连用。
① Mr Li has just bought a piece of new furniture.
② Give me a cup of cold water, please.
③ Please put two lumps of sugar in my coffee.
④ The boy picked up two handfuls of sand from the beach.
⑤ We saw a flash of lightning in the sky.
⑥ The gardener pulled out blades of wild grass from the garden.
⑦ She gave bars of chocolate to the visiting children.
有些名词如 scissors, trousers, spectacles, tongs, pliers 等，都以复数形式出现，如：
⑧ The scissors are lying on the table.
⑨ The spectacles fit me nicely.
如果要给这些名词表示单数“一”的意思，就要借重单位词了。例如：
⑩ Mary has just bought a pair of scissors.
(11) The mechanic repaired the machine with a set of pliers.
现代英语注重简洁，合成形容词便应运而生，其中有一种是用来表示数目的，方法是：
“数目+名词”，如：a five-year plan, a ten-dollar note, a two-hour meeting, a three-day conference等。
必须注意的是，这种合成形容词中的名词，只能以单数形式出现。如果用复数，就错了，如：
a five-years plan, a ten-dollars note, a two-hours meeting, a three-days conference.
这类错误，虽然频率不是很高，但也是要留意才好。
如果没有把握，不妨用完整的表达方式，如：
a five-year plan→a plan of five years, a ten-dollar note→a note of ten dollars, a three-day conference→a conference of three days 等。
