Question

in this way he was able to solve the mystery .( )he did it.1

Answer 1

选 3 that's how he did it.意思是：那就是他如何做到的.

1.that's so 的话,so在这里是代词,所以后面的it 多余了

2.like this 的话,要把它放在最后：he did it like this

4.so 要用的话,是要倒装的,so did he,意思是：他也是这么做的,意思也不对