It's milk 中间为什么不能加a

It's milk 中间为什么不能加a some后面为什么milk不加s 为什么不能加S? 这个It's a milk,有没有错,怎么改,为什么? —What's in the box? —_____ some milk. A.They are B.It is C.There is D.There are不能选B吗正确答案应该是C问一下为什么不能选B the milk smells bad 中的smells为什么要加s The coffee is good.That's right.It will taste __with some milk.A.goodB.betterC.bestD.the besttaste 在此是尝起来的意思,是系动词,后接形容词,为什么不能选A It`s an eraser.为什么加an不加a It's happy to see you again.为什么中间要加to?不加不行吗 It's { } for you { } { } a glass of milk{ }going to bed.上床睡觉之前喝杯牛奶对你有好处.第2个空答案填to为什么?be good for 能加不定式吗 s=sqrt(p*(p-a)(p-b)(p-c));必须写面 s=sqrt(p*(p-a)*(p-b)*(p-c));中间的*号必需要加吗?为什么不加不能运 It's good exercise.为什么good前不用加a? 英语：“put it on为什么在中间加”it呐? It's .that中间加短语还是句子还是都行? Here is a card. Please ------it out. 填单词, I watch TV for long time. 为什么不能在time后加s? It's a quarter past ten和It‘s half past ten为什么quarter前面加a ,half不加? What's that?It's（ ）A.phone B.ball C.book D.milk 选择填空：What's that?___ It's a__.a.bread b.milk c.carrot.