1.The old man is dangerous＿＿＿.Send for a doctor,please.根据句意补全单词.
2.People use computers to woek in the company.（变否定句）
People＿＿don't＿ ＿＿use＿＿computers to work in the company.
3.I didin’t buy the house because it was too expensive.（对because it was too expensive提问）
＿Why＿＿ ＿didn't＿＿ you buy the house?