Here are the completed sentences:

86. Mary visited Van Mieu last Sunday, didn't she? (VISIT)
**Mary **did make a visit** to Van Mieu last Sunday, didn’t she?**

87. You shouldn’t stay up late to watch TV. (HAD BETTER)
**You **had better not stay up** late to watch TV.**

88. When will they widen the road to our village? (BE)
**When **will the road to our village be widened**?**

89. He became a successful pianist despite his disability. (ALTHOUGH)
**Although **he had a disability, he became a successful pianist.**

90. The firefighters spent two hours putting out the fire. (IT)
**It **took the firefighters two hours** to put out the fire.**