30. A: What are your grandpa and grandma doing? B: They _____ __________ (課本p.111)(A) is picnicing.
問題詳情
30. A: What are your grandpa and grandma doing? B: They _____ __________ (課本p.111) (A) is picnicing. (B) is picnicking. (C) are picnicing. (D) are picnicking.