题目

第二节 （共5小题；每小题2分，满分10分）        根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。 Do you constantly use the computer, whether for learning or entertainment? Computers give off radiation that is bad for your health, but here are some ways to protect yourself from computer radiation． ___71___ Green tea can be absorbed by the body easily into a form of vitamin A, which helps reduce radiation．___72___ It is advisable to attach a radiation filter plate （辐射过滤板） in front o先化简，再求值：7a2b+（-4a2b+5ab2）-（2a2b-3ab2），其中a=2、b=3．