Did you arrive here this morning? — Yes, it was at nine o’clock _____ we came here. [ ]

I called you last night but you didn’t answer the phone. – About 8:00 Oh, I ______ with my family at Wal-Mart at that time.

Henry often helps look after Granny Wang,but＿＿＿.

Topics for textbooks and conference books should be_______ to the experiences and interests of the students.

____ will our world ____ if there is only white and black