Up to Tuesday's attack, the worst school shooting in the U. S. was in March 1998 in Jonesboro,________ two boys, aged 11 and 13, shot and killed a teacher and four girls.
Mr Li who is in _____ charge of our class is very experienced.
He is a man of ____ and he had a lot of interesting ____ in his life.
I don’t think _____ possible to master a foreign language without much memory work and practice.
Work hard at your lessons, ______ you’ll fail the exams again.
He devoted all the time _____ his research .