Question

David didn’t give up ______ he had failed in the experiment four times.

A．if

B．while

C．though

D．since

Answer 1

C

考查狀語從句。句意“大衛沒有放棄，盡管他做實驗已經失敗四次了。”A引導條件狀語從句；B引導時間狀語從句；C引導讓步狀語從句；D引導原因狀語從句。故選C。