植物幼苗的“工厂化”生产利用的是( )
A:组织培养
B:嫁接技术
C:无土栽培
D:快速催种
____ ____ ____ = ____
—I . But I had some urgent business to deal with then.
They got two free tickets to Canada; otherwise, they'd never have been able to ______ to go there.