Unit 12 Life is full of the unexpected.,Section B 1 1a-1e,根据句意及括号内所给词的提示填空。1. Dennis _(study) English for four years before he _(go) to the USA.2. Wu Dongs parents _(not have) any news about him for three months until he _(call) them yesterday.,Revision,had studied,went,hadnt had,called,3. Henry _(collect) more than 100 foreign stamps before he _(join) the stamp collecting club.4. By the time I _(get) home, my father _(leave) for New York.5. I _(memorize) 900 English words when I _(be) ten.6. He