Question

They have made so great progress      .

A．three years ago	B．for three years
C．in the past three years	D．before three years

Answer 1

C

考查時態(tài)。“in/over/for+一段時間”常和現(xiàn)在完成時連用。A用于一般過去時。句意“在過去的三年里，他們已經(jīng)取得了如此大的進(jìn)步。”故選C。