问题详情

We (are obliged) to grow up in skepticism, requiring proofs for every assertion about nature, (but) there is no way out (except) to move ahead and plug away, hoping for comprehension in the future (but) living in a condition of intellectual instability fo
A．are obliged
B．but
C．except
D．but请帮忙给出正确答案和分析，谢谢！