.—You must apologize to Rebecca for being so rude, Sam.—Why ________ I say sorry? It’s she ________ said insulting words first.
My father was disappointed ____ the news.
His teacher was angry ____ him ____ his being late.
She felt disappointed when she found out they had gone swimming____ her.
We left Xi' an _.___ a very hot summer afternoon.
The teacher is busy ____ teaching.