1, There has been a slight drop in the number of people using public transport (slightly) → ...................................................... 2, Revising for exams takes up all my time at the moment (busy) → ...................................................... 3, There was an increased demand for travel , sothe government decided to invest in building the very first metro systems (as) → .......................................................... 4, I don't know much about historical events , so I can't help her with her history homework (if) → ............................................................. Thu gọn viết câu trúc nhé