.________ gas leaks and similar accidents should occur, some responsible persons should regularly inspect all the laboratories.

. Put on your rain()coat ________ it rains.

. ________ the case is settled out of court, it can often take years before it comes to trial.

. I won’t make up with him ________ he apologizes.

�. While teaching students, teachers should take into consideration _________ students develop at different rates.

�. The thought worried him much ________ he might fail in the exam.

.He got up very early that day ________ he caught the first train.

. ________ they will not come to join us, we have to change our plan.

. There are dirty marks/spots on her trousers ________ she had wiped her hands.

. You should make it a rule to leave things ________ you can find them again.