1.Is this factory_____some foreign friends visited last frid

1.Is this factory_____some foreign friends visited last friday
A.where B.the one
2.The wolves his themselves in the places____couldn't be found
A.that B where
3.May the fourth is the day _____we will never forget
A.WHICH b.on which
4.I have mang books,some of ____are on chemistry
A them B.which