This is _____ orange and that is _____ ruler.

He was caught smoking while working in the gas station. So dangerous! He should have been warned of the potential risk.—________, but he ignored my warnings.

The teacher tells his students to read the novel over and over again until they ______ it

comfortable seats.

What do you think of the science exam—Very difficult! We all find ______ the most difficult one we have ever taken.