一盒粉笔是a box of chalk 还是 a box of chalks ?为什么牛津高阶里写的是a box of chalks ？

关于chalk一支粉笔是a piece of chalk那么一盒粉笔是a box of chalk 还是 a box of chalks 一盒粉笔是a box of chalk 还是 a box of chalks ?为什么牛津高阶里写的是a box of chalks ？ She ____(buy) a box of chalk yesterday The teacher picks up a __ of chalk from the chalk box. chalk不可数,但彩色粉笔可数,那么“一根白色粉笔”可以说成a white chalk 因为彩色粉笔可以是可数的,所以我要问是否可以说a red chalk ,a white chalk?因为白色也是一种颜色呀. with a chalk和 with chalk哪个是正确的?为什么?chalk 可数不可数可不可以用 a piece of chalk a piece of chalk改成a chalk不行吗?为什么要加piece of啊?chalk好像是可数名词啊,粉笔不是论根的吗? 关于chalk的单复数问题We need a box of coloured________,but he bought us some white ________ instead.答案选：chalks,chalk为什么第一空是复数?答案对么?chalk不是不可数的么? 填入句中所缺的词 The teacher picks a ___ of chalk from the chalk box chalk的中文意思是什么?是粉笔 I want a large box of chalk 和 I want a large box of the chalk 加the 什么用这个the呀? there are ____(一盒巧克力)on the table.,一盒巧克力是：a box of chocolates,这该怎么 And I want a large box of chalk,too. 有and为什么还要加too 英语连词成句 too want chalk larg I a box of 一盒蛋糕是a box of cake还是a box of cakes?为什么要是一袋苹果是不是a bag of apples?苹果必须用复数? 许多只粉笔 many____ of chalk 大意 main____ chalk pastels是什么? 跟粉笔是一个东西吗? 一盒粉笔24支,那么7支粉笔是一盒粉笔的几分之几