--When did the World Exposition(世博会) in Shanghai begin? --The Expo began ________ May 1, 2010.
—Why was Miss Lee angry this morning?—Because Tom didn’t _____ his homework.
We are made ________ more confident by our teacher.
He is an explorer ________ a sailor.
________ our surprise, he failed the math exam.
He ________ an English club last year and has improved his English a lot.