请教语法

好运当头照

   While play is important at all levels of human

   development, _________ takes on particular

   significance when children are five and six years old.

         a)it   b)and  c)which  d)beacuse it

答案是a  我觉的d对啊

Lactose, a sugar present in milk, is one of simple sugars used in food

preparations for infants.

答案是c 为什么

Jackson, Michigan, a city who was settled in 1829,

was named for Andrew Jackson,  the seventh President of the United States.

答案是b为什么

[此贴子已经被作者于2005-3-14 6:15:13编辑过]

redpassion

While（虽然） play is important at all levels of human

   development,这里是主句--> it  takes on particular

   significance when children are five and six years old.

好运当头照

谢谢指点

ncraig

1：个人认为对句子的意思理解以后再做就不会犯错

2：is one of simple 改成is one of the simple 吧~

3：city是物不是人，要用which