Part 4

　　① 主题提示：澳洲火蚂蚁的起源，特征，巢穴和生态作用 Red imported fire ants

　　31-40）completions 

　　31. fire ants live in environment except for desert and artic areas

　　32. carried in soil with farming equipment

　　33. fire ants was first found in Brisbane in 2001, it is near the port

　　34. often being found under rocks

　　35. aided by well-trained dogs

　　36. prevent people from getting water they need accessing the…

　　37. camera wired to helicopter

　　38. insecticide and bait mixed with corn combined with…

　　39. reduced the use of sport/support facilities

　　40. damage the electrical system

　　② 主题提示：古代食物Ancient time food research

　　31-40）completions

　　Background

　　Indirect evidence

　　31. From graphic evidence to social evidence

　　32. undigested contents in stomach ……

　　Direct evidence

　　33. Studied food remains in pots 

　　34. 暂时缺失

　　35. prepared and ate food

　　36. researchers can determine the knives kind by bones of animals remained

　　Indirect evidence

　　37. Chemical signature on bones

　　38. food sticking to teeth

　　39. fossil was not easily found because…is extremely common 

　　40. investment is risky, which can be natural disasters, political event, or people’s climate