accident, accidental, accidentallya.I didn’t think our meeting was __________—you must have known I would be there.b.I __________ locked myself out of the house.
distribute, distribution, distributivea.The company has decided to take Nanjing as its ___________ base.b.Copies of the book were ___________ free to each school in the district.
微信支付 
支付宝支付