蒸し暑い
The classroom is muggy.
教室の中は蒸し暑いです
The classroom is terribly muggy.
教室の中はひどく蒸し暑いです
The classroom is more terribly muggy than usual.
教室の中は普段よりひどく蒸し暑いです
The classroom is more terribly muggy than usual because the students are all packed in.
教室の中は学生が集まっているため普段よりひどく蒸し暑いです
The classroom is more terribly muggy than usual on a rainy afternoon because the students are all packed in.
教室の中は雨の午後に学生が集まっているため普段よりひどく蒸し暑いです