水稻产量构成的要素主要有（） 亩穗数；。 亩株数；。 千粒重；。 穗粒数；。
A historical study of language is a （）study of language. synchronic。 diachronic。 prescriptive。 comparative。
避税地
In modern linguistics, speech is regarded as more basic than writing, because （） in linguistic evolution, speech is prior to writing。 speech plays a greater role than writing in terms of the amount of information conveyed。 speech is always the way in which every native speaker acquires his mother tongue。 All of the above。
我国目前生产上大面积种植的油菜类型属于（） 白菜型；。 甘蓝型；。 芥菜型；。 其它；。
下列哪些国家属于上海合作组织成员（）
