基础导练
Ⅰ. Fill in the blanks according to the given tips, using thei r proper form.
1. I _____(be) to Beijing several ti mes, but I still want _____(go) there this vacation.
2. Mike _____(have) this phone since last September. He _____(buy) it when he just started to work.
3. We _____(not meet) each other for five years. Both of us _____(leave) the factory in 2009.
4. The hospital _____(be) there for 15 years. It _____(be) the tallest building in our city.
5. The children _____(never visit) the Great Wall before. Their parents _____(take) them there next month.
