我这有个英语题，我见过3种回答了，拿不准的别来！
2、It is cold.It was much colder yesterday.(合并为一句）
It ______ much _______ yesterday than ________ today.
特别是第3空，我见过it's , is , it！
参考答案:was colder it's
全句为：It was much colder yesterday than it's today.
这是表语之间的比较，因此第三个空要把主语和系动词都填上。