變一般疑問句的規(guī)則是有be動(dòng)詞時(shí),提前be 動(dòng)詞；沒有時(shí)提前助動(dòng)詞.
比如一般現(xiàn)在時(shí)：
He likes English.變?yōu)?Does he like English?
They go to school by bus everyday.變?yōu)?Do they go to school by bus everyday?
現(xiàn)在完成時(shí)中have/has是助動(dòng)詞.所以變一般疑問句時(shí)要提前助動(dòng)詞have和has,在這里它們沒有實(shí)際意義,不表示“有”的意思.只是輔助形成完成時(shí)態(tài).也就是說,它們之于現(xiàn)在完成時(shí)的作用相當(dāng)于do/does之于一般現(xiàn)在時(shí)的作用.例如:
They have already lived here for three years.變?yōu)?br/>Have they already lived here fro three years?