题目

在△ABC中，若_________。 答案：  【解析】 试题分析：∵，∴，∴ 考点：本题考查了正弦定理的运用 点评：熟练运用正弦定理及其变形是解决此类问题的关键，属基础题2．My name is Peter Kalmus．I'm an atmospheric scientist and（61）afather of two happy boys．I also grow food and largely avoid（62）burning（burn） fossil fuels，which requires some creativity in today's world．I now emit about 1 ton of CO2 per year，down from 19 tons per year，（63）whichis about the U．S．Average．A few years ago，my awareness of global warming reached the point where I had no choice but（64）to respond（respond） in some meaningful way．But this is a tall order：global warming is rather complex，combined（65）deeply（deep） with our lives，physically，socially，and spiritually．How can we respond as individuals？What can we do，right here，right now，with what we have？How can we live happy and fulfilling lives in the shadow of global warming？I（66）have written/have been writing（write） a book recently describing my response to the（67）ecological（ecology） dilemma we're now in．Our dilemma has deep roots（68）inour society，our structures of thinking and belief，（69）andthe ways we relate to the biosphere，each other，and（70）ourselves（we）．The book is forthcoming from New Society Publishers，due out in spring 2017．