英文文法概念: 1. 英文句子中, 單數主詞 + 單數動詞 (1) One third of the cake is eaten by Tom.單數主詞是One third of the cake,所以單數動詞用is。 (2) Two thirds of the cake is eaten by Tom.單數主詞是Two thirds of the cake,所以單數動詞用is。 注意: à句子(1)(2)中,不論是One third of the cake或Two thirds of the cake. 真正主詞都是the cake(單數),因此動詞都是單數動詞is。 2. 英文句子中, 複數主詞 + 複數動詞 (1) One third of the books are mine.à真正主詞是the books (複數),因此動詞是複數動詞are。 (2) Two thirds of the houses are mine.。à真正主詞是the houses (複數),因此動詞是複數動詞are。