Humans readily change tools to suit the circumstances: once a basic knowledge of tool-maki

Humans readily change tools to suit the circumstances: once a basic knowledge of tool-making has been acquired, it is a simple matter to make something more suitable for the job【C1】______ . So early people made not only hand axes for chopping, but also smaller knives and scraping tools with which to cut meat and【C2】______ fat off the skins. It is clear from archaeology that humans were【C3】______ from very early in history to exploit a much wider range of food resources than other【C4】______ . In particular they were frequently able to eat meat; the diet of apes is normally vegetarian(食草的), consisting of grass, leaves, and shoots,【C5】______ by insects and grubs. With tools such as spears and bows, early humans were able to【C6】______ larger animals. Spears and nooses(套索, 陷阱)could be used to catch birds and smaller animals,【C7】______ fish could be taken with nets and traps set on the river bottoms. Excavations(出土文物)made at the living sites of early people have revealed bones from the animals that they ate, while also providing【C8】______ of their ingenuity(精巧，独创性). Some of the bones found in the cave of Makapansgat in South Africa show signs of being【C9】______ broken and divided into types suitable for different purposes as tools. Tools also enabled humans to【C10】______ food in specially made containers of wood or baskets, so that times of shortage could be lived through more easily.

【C1】

A．by hand

B．to hand

C．at hand

D．on hand

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