III,选择合适的词并用其适当形式完成句子2

III,选择合适的词并用其适当形式完成句子2
history ; historical ,historic
(1)After a long time's discussion,the two great leaders signed a ____ treaty.
(2)Mr Liu is our ____ teacher,who is good at studying ____ research.
3,occur; happen,take place
(1) A terrible fire _____ at that hotel last night.
(2)Great changes have_____ in our homedown since 2008.
(3) Something must______ to John,because he hasn't turned up.