3. 下列不定代词作复数用：“（a）few, many, several，both”等。
         Few (of the guests ) were familiar to us . 没几个（客人）是我们熟识的。
         Both / Both (of ) these are interesting . 两部影片都有趣。
4下列代词须视其“具体所指”来决定谓语动词的单、复数：
     1）“what ,which ,who ,whose ”等。
                    Who is your brother ?你兄弟是谁？
                    Who are League Members .哪些是团员？
     2） “all, some, more, most, any, none, a lot(of ), lots (of ),”等。
                    All (of the students) are working hard .（所有的学生）都在用功。
                    All (of the paint) is fine .（这些油漆）都很好。
     3） “half(of), plenty (of), the rest(of), (a)part(of), the remainder(of )余下的）”等视被修 饰词的单复数而定。
            Half of the apples are bad .苹果中有一半是坏的。
            Half of the apple is bad .这只苹果坏了一半。

Ⅲ. “数词”、“数量、单位”等词语作主语时：
1. 表示“运算”的数词通常作单数 。

Ten times four makes (make) forty . 十乘以四得四十。
2.表“时间、距离、金额、度量衡”等的词语，作“整体”看时作单数用，侧重指“若干   单 位”时作复数用。
             Twenty years is not a long time. 二十年光阴，弹指一挥间。
               Twenty years have passed since he left. 他离开已二十个年头了。
3.“分数、百分数”通常依其“具体所指”来决定单、复数。
         About 40 percent / two-fifths of the books here are (is) worth reading.    

               这些书中百分之四十/五分之二值得读。
          Only sixty percent / three-fifths of the work was done yesterday.              

         昨天只干完了百分之六十/五分之三的工作。
4. "a number of (许多)/ a variety of (各式各样) "+复数名词，常作复数用。
  A number of students in this class are (is) from Sichuan.                  

这个班有不少同学来自四川。
           There are a variety of toys in this shop.这家商店有各种各样的玩具。

l         注意:

“the number(数目)/ the variety(种类)”+ of + 复数名词，作单数。
The number of students in this college has doubled . 这所大学的学生人数翻了一番。
The variety of goods in this shop is rich . 这家商店货物品种丰富。

IV．单、复数同形或易混淆的词作主语时：

1.一些以“-s”结尾表示学科、疾病和游戏的名词（AIDS, athletics, draughts, politics, economics, mathematics, measles, physics, statistics）等作主语，谓语用单数形式。

Mathematics seems easy to me .我似乎觉得数学不难。

2. “works工厂，means方法，series系列，species物种，aircraft飞机”等名词的单复数同形，要从上下文判断其具体意义来决定谓语动词的单、复数。

This works was (These works were) built two years ago .

这（几）家工厂是两年前修建的。
Every means has (All means have) been tried . 各种办法都试过了。

l         注意:

这类名词通常还有“fish ,deer ,sheep, plastics, manners(礼貌) , whereabouts (行踪) ”等。（但news（消息、新闻）是不可数名词，通常只作单数用。）