The big box is too heavy for me to carry,后面为什么不加it
问题描述：
The big box is too heavy for me to carry,后面为什么不加it
答
The big box is too heavy for me to carry.这是你的原句,句子主语是the big box~现在把the big box换成it 就会变成It is too heavy for me to carry～carry后面同样不再加it～
因为carry 承担的宾语就是前面的主语,如果再加it就会和前面主语重复,而且这是个系表结构的句子,不需要宾语.