It was along the Mississippi Rever ____Mark Twain spent much of his childhood.
I don’t know ________ is in charge of English department.
---Susan is so excited!---Oh, yes! She is busy preparing for her trip to Africa that she _____ for years.
I know a little bit about Italy as I _____ there several years ago.
It is the first time that Michel _______ the Summer Palace.
--- Jenny, do you remember the first time we met?--- Sure. You ______ the suitcase at the airport.