Mr. Green has two sons, and one of ______ is working as a bus driver now.

Some insects the color of their surroundings to protect themselves.

After reading for an hour, you’d better ________ the green trees for a minute or two.

What do you think of the play— Oh, It’s the __________ one I have ever seen. I nearly fell asleep!

Travelling on the bad mountain roads is a(an)________ experience and I will never risk my life like that.