This is the first time I ______ such beautiful music .

There was no ______ that she was a good teacher.

What’s the noise ? It sounds as if it comes from upstairs.   --______. It must be the window-cleaner working , next door.         

He ____ in the north, but now he ____ here．

It was my sister ________ first had the idea to cycle along the entire Mekong River.