Reading process suggestion

Hey guys, I’m taking some reading practice tests these days, and after blowing through the vocab, I try to move on to the 3 choices main idea question, but sometimes it takes a lot of time for me to read the whole article and figure out the main ideas of each passage at once…

So I’m wondering which is more efficient: to read the whole article and do the main ideas question first, or just go through the questions 1 by 1 (after vocab) and get each of the main idea of that passage. Do you guys have any suggestions?