Yesterday, when I went past the classroom, I _______ someone _______.

I __________ my pen everywhere, but I didn’t find it.

What’s _____most useful invention in the 20th century? —_____ computer, I think.

Which of the two English dictionaries will you buy?——I’ll buy ________ of them, so I can give one to my friend Helen.

Whose sweater is this? —It looks like John’s. Oh, yes. It’s __________.