问题

scientists have done a lot of research on A (H1N1) flu, there are still some cases for further study.[ ]

A: As
B: One
C: If
D: Although

正确答案是：

标签： done , lot , scientists

同类题型

Add the onion and the tomato the sandwich.[ ]

Anna doesn’t _______ a black skirt. —But she ________ a red one.

Mother Teresa devoted her life _______ caring _____ the poor.

Simon is willing to help others ______ with their English.[ ]

It’s time ______ lunch. [ ]