[解析]
M:What is that strange smell?Did you take the trash out?
W:Yeah.Oh,it is the gas.I'll open the windows and let fresh air come in.Can you turn off the gas?
M:But I looked everywhere.There's no gas leak.Then it must come from Mr.Thompson's.Mr.Thompson went to Australia for sightseeing.Did he return?
W:He came home a quarter of an hour earlier than you.When you got back home,the clock had just struck six.It's 6:30 p.m.now.Hurry up,let's knock on his door.
M:We need to grab wet towels and cover our noses in case of an accident.