______ the agreement was reached without conflict.

— I think it’s beneficial to build a library near our dormitory building.—  　　　. It will be a great convenience.

Thinking that the students were having an evening class, the teacher left the classroom, _____.

John is very lazy. He falls ______ behind among the students.

—Must I turn off the gas after cooking ? --Of course . You can never be ___ careful with that.