A. epidemic B. nicotine C. scientific D. vicious A. twofold B. introduce C. overseas D. terribly A. branch B. alienate C. account for D. safety belt A. maid B. aerospace C. circulate D. crowd in A. subject B. career C. kick D. kill A. congratulation B. thinker C. application D. family tree A. related B. electrode C. become interested in D. convenient A. iron B. poisonous C. for certain D. actress A. state B. clap C. below D. sun A. in many ways B. fear C. Halloween D. unite