extending与expanding有什么不同

英语翻译
The Japanese businessman,arms extending downwards from his shoulders,bowed from his waist toward the American businessman to whom he was just introduced
arms extending downwards from his shoulders

This is a region of very flat ground extending from the Canadian border to the Gulf of Mexico,and eastward as far as the Appalachian Mountains.
这里的as far as
和什么什么一样远?就什么什么而言?

英语选10词填空求助谢谢

or; other; extending; adopt; as; with; alternative; respect; respond; from; unless; that; what; resistant; transmit

SAT语法IE题,
1.Flints found in the rgion extending from the Nile Valley to the highlands of eastern Iraq (attests to) the presence of people there as long ago as one hundred thousand years.
2.(In a world that) the rate of technologival and social change accelerates frighteningly,change itself often seems to be the only constant.
3.The Mount Isa mine complex is one of {the most highly mechanized} in the world,(plus being) the largest single industrial enterprise in Queensland.
错的都用（）标注了,请问错在那里,怎么改正?最后一句{}里的不应该是名词吗?为什么是对的?反而PLUS BEING错了?

An Invitation Create a conversation about extending an invitation.Student A is to invite Student B
不是翻译，是编一个对话
Create a conversation about extending an invitation.Student A is to invite Student B to come over for dinner this weekend.But Student B is busy at that time.So they make an appointment on next weekend.Use the expression of extending,declining and accepting invitations.

求解释一句英文
extending a 5-year trend in which companies have lagged in promoting and mentoring of women to their own detriment,
这个句子为什么要用in which 还有their 指的是哪个?