The conference has been held to discuss the effects of tourism _______ the wildlife in the area.

 They stood there and ______ each other as if they were going to fight.

Up to now, the little boy is still unable to _______ to us what he meant just now.

At the meeting, the old man ______ some good advice about bringing down the market price of housing.

 I can hardly hear the radio. Would you please _________