The students are warned not to talk about anything______ to the accident that happened the other day in the school.

age of 14, Father had to leave school and start working. There would be no one to support the family _______ he not worked.

nservation area is very important for preservingmany animals and plants, which would ______ run the risk of becoming extinct.

Can I ______your dictionary—Sorry，I’m using it.

__ what I had previously thought, my new biology teacher turned out to be a rather interesting person.