Question

the reason why i was alone in the mountains is that i had a

Answer 1

是表语从句,用在be动词后面,这个从属连接词that只起连接作用,是无名英雄,在从句中不作任何成分,如：

The problem is that I can't speak French.

The problem is that I can't type Tibetan.

但是在口语中把that常常省略掉,然后在省略处加一逗号,写成：

The problem is,I can't speak French.

在正式文体中,从属连接词that是不能省略的.

希望我能帮助你解疑释惑.