68. The Summer Palace is one of the _____ parks in Beijing. I suggest you going there to have a visit.
The person we spoke to ____ no answer at first.
The person we talked about ____ our school last week.
Before he went abroad,he spent as much time as he _____ English.
______ is it _____ has made Peter _____ he is today?
If _____ carefully, the experiment will be successful.