This accident was______ his driving.
The environmental organization calls on customers not to purchase these _______ packages of food, clothes and gifts.
People are advised not to smoke at home, since passive smoking is ________ to people around them. Which is Not proper for the blank?
He stumbled(绊倒)on the _______ ground and fell flat on his face.
Many students today suffer from ________ problems, since they are under too much pressure.
________ energy is generated from natural resources—such as sunlight, wind, rain, tides and so on.