(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 時
定冠詞何時要有何時要無？
本題教科書是寫(1)