单项选择题
A．the cut surface can heal more quickly B．open wounds on the tree run the less risk of getting diseased C．a gardener can do pruning more easily D．the leaves can interfere
A．During a storm, lightning damaged cable. B．Because of unemployment. C．Heat waves had made people use too much electrical power. D．Because the looters damaged the electricity supply.
A．everything that was known B．law and something about medicine C．many new subjects D．the subjects that interested students