nally, the job as a teacher _____ be challenging, for I sometimes _____ deal with some smarter but less diligent students.

The number of the students in our school ____ rising since 2006.

The little girl is walking along the beach, happy and joyful, ________ bending down to pick up a beautiful seashell

There was a heavy curtain ________ the light.

Not until the early years of the 19th century ___ know what heat is. [ ]