兔眼蓝莓属于自花不结实树种（ ）。

A、二极管正向导通时，流过的电流很小；反向截止时，流过的电流很大
B、任何情况下，二极管的正向导通电压都可以忽略。
C、理想二极管正向导通时，相当于开关断开；反向截止时，相当于开关闭合。
D、理想二极管正向导通时，相当于开关闭合；反向截止时，相当于开关断开。

are claimed to make smoking to some extent safer, but they can only marginally reduce, not eliminate the hazards.7. What conclusion can we draw after reading this article？A．The effect of cigarette smoking on health is not so much．B．Smokers would often die from lung cancer．C．We should not neglect the bad influence of smoking, so don’t smoke or don’ t start to．D．More and more physicians and research workers are less sure of the effect of cigarette smoking on health．