完成句子。应该采取适当的措施限制外国旅游者的数量(measuresbetakento)，努力保护当地环境和历史不受国际旅游业的不利影响。(effortsbemadeto)用被动句：

Question

完成句子。

应该采取适当的措施限制外国旅游者的数量(measures be taken to)，努力保护当地环境和历史不受国际旅游业的不利影响。(efforts be made to)

用被动句：________________________

Answer 1

答案：解析： Proper measures must be taken to limit the number of foreign tourists and great efforts should be made to protect local environment and history from the harmful effects of international tourism．