春天播种，秋天收获的作物叫（）.
参考答案：大春作物
—What do we need to buy?
—We need__________. [ ]
A. two carton of milk
B. two cartons of milks
C. two cartons of milk
D. two carton of milks
淋巴细胞能形成E花环是因为其细胞膜上具有（）。
A.CD2
B.CD3
C.CD4
D.CD8
E.CD28
