他在考试时犯了个愚蠢的错误，把加号看成了减号。

He ___goofed during the exam by mistaking a plus sign for a minus sign.

别胡闹了，现在是上课时间。

Stop ___goofing around, it's class time now.

别像个傻瓜一样在雨中跳舞。

Don't act like a ___goof and dance in the rain.