The chemistry teacher asked the students ________ more attention _________the lab clean.
There is a wooden bridge ______the river _______ my house.
-- _____ I ask you a question, Mr. Wang?-- Yes, you _______.
-- I like playing _____ piano.-- Oh, we have _____ same hobby.
-- Congratulations! You've got a chance to be an exchange student! --________
-- Shall we join in the Green World Summer Camp? --_________