(1). The lower portion of V1 represents the top half of visual space.
(2). The lower portion of the V1 represents the top half of visual space.
(3). The lower portion of V1 represents the top half of the visual space.
(4). Lower portion of V1 represents the top half of visual space.
到底 scientific writing 时
定冠词何时要有何时要无？
本题教科书是写(1)