教练听到裁判的误判后忍不住骂了几句脏话。

The coach couldn't help but ___swear when he heard the referee's wrong call.

我发誓会永远支持你。

I ___swear I will always support you.

我发誓昨晚真的看到流星了。

I could ___swear I saw a shooting star last night.