题干
-- My grandparents are too old ______.
-- Yes, but they should often have a walk.
A：to work
B：works
C：work
D：working
答案(点此获取答案解析）
A
-- My grandparents are too old ______.
-- Yes, but they should often have a walk.
A：to work
B：works
C：work
D：working
