`8.` This exercise can be done ourselves.
`9.` He used to help me.
`10.` The weather was bad, so we postponed the picnic.
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`1.` inventors (những nhà phát minh)
`2.` cultural (văn hóa)
`3.` Enviromental (thuộc về môi trường)
`4.` Communication (sự giao tiếp)
@ `Ly`