We often think of the days ______ we spent together on the island
A when B which C in which D during which

It was in 1969 ___ the American astronaut succeeded in landing on the moon.
A that　B which　C in which 　 　 D when

 It is the third time __ late this month
Athat you arrived Bwhen you arrived C that you’ve arrived D when you’ve arrived

This is the museum ______ you saw the other day.
A that B where　C in which D in that

 This museum is ______ you visited the other day
A that   B which  C where  D the one

This is the museum ______ we saw an exhibition the other day.
A that　B which C where 　 　 D in that

Air, ______ we breathe every day, is around us all the time.
A that B / C which D it

 Is oxygen the only gas ______ helps fire burn?
A that        B /   C which     D what

 This is the biggest lab ______ we have ever built in our university
A which  B what  C that   D where

 I can tell you ______ he told me last week  
A all which    B all what         C that all            D all that