—Where did Lily go yesterday?
—She ______ to visit her grandpa with her parents.
句意：——莉莉昨天去哪了？——她和她的父母一起去看望她的爷爷了。问句中时间为yesterday，提示答语用一般过去时，故答案为A。
—You look tired. What's wrong with you?
—I ________ well last night.
根据last night可知，要用一般过去时，故答案为C。
She ______ to an engineer for 15 years.
句意：她和一位工程师结婚十五年了。表示“结婚”，而且和时间段 for 15 years连用的结构是 be married，故答案为C。