Richard was very strict with his two daughters,______them to compete against each other.

           in thought, he sat at the edge of the bed, with his eyes           on the letter in his hand.

The oceans and seas ______ the islands are more or less polluted.

He is very popular among his students as he always tries to make them ____ in his lectures．

When I called at his home the other day, I found him sitting on an armchair,_____ in his hands.