After the arrival of hunter-gatherers in the southwestern region of North America(状语从句), several alternative types of agriculture emerged(主句), all involving different solutions to the Southwest’s fundamental problem(独立主格结构作状语): how to obtain enough water to grow crops i...
回答于 1秒前
The marginal wetlands that remain continue to be threatened by reclamation for farms and homes. that remain是定语从句,谓语是continue。
回答于 1秒前
想想为什么会有形式主语?是因为主语较长,会引起整个句子头重脚轻不平衡。什么情况下主语会比较长?动名词,不定式和主语从句充当主语的情况下。形式宾语也是如此。另外,什么词性能作主语呢?介词短语可以吗?
回答于 1秒前
回答于 1秒前