I couldn’t _______.The line was busy.
To understand the grammar of the sentence,you must break it______ into parts.
The classroom is big enough , but we’ll have to move if we have more students.
—You know. Bob is a little slow ____ understanding, so…— So I have to be patient ______ him.
Mark was a student at this university from 1999 to 2003, ____ , he studied very hard and was made Chairman of the Students' Union.
The accident is reported to have occurred __________ the first Sunday in February.