—Did ________ of your parents come to attend the opening ceremony? — ________ of them came. 

--- You know Brad Pitt is already fifty． --- You are kidding．He doesn’t look __________ ．

I think Mrs. Stark could be _______ between 50 and 60 years of age.

-----How many students are there in the classroom?------_______.

--How many eggs are still there in the fridge, Bill? ---_____.