—It was terrible. It rained ________. People could _______ go out.
A:hardly; hardly
B:hardly; hard
C:hard; hard
D:hard; hardly
像马铃薯这样,不经过两性生殖细胞的结合,由母体直接产生新个体的生殖方式,叫做____生殖.这种生殖方式的特点是,繁殖速度快,子代能稳定地保持母体的遗传性状,但这种生殖方式产生的后代____有下降的趋势.
若﹣3x2my3与2x4yn是同类项,那么m﹣n=( )