题干
—When is Jay's concert?
—It's __________ three o'clock __________ the afternoon of July 18th.
A：at, in
B：at, on
C：on, in
D：in，on
答案(点此获取答案解析）
B
—When is Jay's concert?
—It's __________ three o'clock __________ the afternoon of July 18th.
A：at, in
B：at, on
C：on, in
D：in，on
胚胎干细胞 ④造血干细胞 ⑤神经细胞