漏电的结果,不仅会引起(),而且还将使绝缘进一步恶化,以致发展成相间短路;
参考答案:人身触电
现代农业育种专家采用诱变育种的方法改良某些农作物的原有性状,其原因是[ ]
A. 提高了后代的出苗率
B. 产生的突变全部是有利的
C. 提高了后代的稳定性
D. 能提高突变频率以供育种选择
Although they __________ in love for over ten years, they haven't decided when to get married. [ ]
A. have fallen
B. had fallen
C. have been
D. had been