Play, often ________ as an activity for younger children, is still important in the social development of teenagers.
We’ve made up our mind to finish this experiment no matter ___ difficult it was.
His doctor suggested he ___ smoke because of his illness.
---It’s a wonderful party.—It’s very nice of you to come.___.
He ___ at the enemy, without saying a word.
She didn't answer the phone.She ___ be asleep.