備戰(zhàn)托福寫作 別小看標(biāo)點(diǎn)符號(hào)!

1：在并列連詞(and， but， for， nor， or， yet )前使用，用來連接句中的各分句。

　　The principal reason for this is that none of them possesses chlorophyll，and since they cannot synthesize their own carbohydrates， they obtain their supplies either from the break down of dead organic matter or from other living organisms.

　　2：用逗號(hào)來分隔一系列單詞、詞組和從句。

　　Further more the walls of fungal cells are not made of cellulose， as those of plants are， but of another complex sugar like polymer called chitin， thematerial from which the hard outer skeletons of shrimps， spiders， and insects are made.

　　They are a major cause of structural damage to building timbers， a cause of disease in animals and humans， and one of the greatest causes of agricultural losses.

　　3：逗號(hào)用來分隔與句子其他部分密切相連的簡短插入語或旁白。(較長的，為突兀的或復(fù)雜的插入成分的則用破折號(hào)或圓括號(hào)。)

　　Chemical fertilization，for example， helps to produce better crops， but is harmful to the environment.

　　4：在并列形容詞，即分別修飾同一個(gè)名詞的形容詞之間使用逗號(hào)，但也有的形容詞之間不加逗號(hào)的。

　　For men， heroism was usually described as bravery and the active，successful over coming of adversity.

　　5：用逗號(hào)來分隔非限定性修飾語，即該修飾語對(duì)于句子的意義并非必不可少。非限定性修飾語與限定性修飾語的區(qū)別在于，它即使被省略，也不會(huì)改變句子的主要意思。

　　(1) 同位語。

　　The canopy， the upper level of the trees in the rain forest， holds aplethora of climbing mammals of moderately large size， which may includemonkeys， cats， civets， and porcupines.

　　(2) 從句。

　　The canopy， the upper level of the trees in the rain forest， holds aplethora of climbing mammals of moderately large size， which may includemonkeys， cats， civets， and porcupines.