ようとした{が/けれど/ら}
Usage
V-vol とした、the past form of V- volとする is used:
In situations where someone had made an attempt to do something but failed
Where someone was going to do something but didn't
Where something happened when someone was going to do something
としたが/けれど tried to - but, was going to - but
としたら = when - was going to -
Examples
ケーキを作ろうとしたけれど、卵がなかったから、作れなっかた。
I was going to make a cake, but I did not have eggs, so I did not make it.
宿題をしようしたが、友達が来たから、するのをやめた。
I tried doing my homework, but then my friend came and I stopped doing it.
家を出ようとしたら、雨が降ってきた。
When I was going to go out of the house, it was raining.