英语选择题求解答（请写出解题思路）
1._____ his talk,Peter has brought along five objects.
A.Illustrate B.To illustrate C.Illustrated D.To have illustrated
2.-Where is the cat?-It is in the kitchen_____ the fire broke out.
A.that B.which C.in that D.where
3.The desire of humanity to do better - to run faster,to soar higher and to push farther - is ____ the Olympics are all about.
A.what B.which C.that D.why