1.How long has it been since we meet last time?
It's been almost one and a half year.
2.When did you see that girl last time?
I saw her last Wendesday.
3.When shall we went to see the patient in the hospital What shall we buy?
4.Can you help me to buy some cold medicine?
5.The last time I saw him was three years ago / in 2010.
6.How many years ago was it when you saw him last time?/ Which year was it when you saw him last time?