Thinking that the students were having an evening class, the teacher left the classroom, _____.
As we all know, apples are sold by ____ weight, and socks are sold by _______dozen.
Many difficulties have ______ as a result of the changeover to a new type of fuel.
——Why are the tax collectors so busy? ——Many people prefer to have their tax forms completed by a professional rather than ___.
It was in the small house _______ was built with stone by his father _______ he spent his childhood.
Nothing that he suggested _____ to be of any use.