未知题型
天敌这一生态因子属于 ( )
D生物因子指同种或异种生物之间的相互关系，如种群结构、密度、竞争、捕食、共生和寄生等。
未知题型 They were brought up under the same roof when they were young.英译汉
未知题型 The new stadium should have been built by now.英译汉
未知题型 It is indeed a most pressing problem.英译汉
