若a<0,ab<0,则化简|b﹣a+3|﹣|a﹣b﹣9|的结果为( )
﹣6
禾谷类作物的叶片,根据其生长先后和着生部位,大致可以分为下、中、上三层,一般认为,()其光合产物供给根系、分蘖、幼叶等营养器官生长为主;()供给茎秆、穗的生长;()供给结实器官。
When we have agreed broadly on what should be said, the secretary will produce a preliminary ()for the committee's approval.
A.project
B.design
C.draft
D.drawing