Well, the test that you're taking is a part of your English language proficiency skills and therefore writing answers in the correct spelling is essential. Even if you know an answer and misspell it, it will be marked wrong. Therefore, pay attention to big words. Each answer carries one mark, so for every wrong answer, there is a loss of one mark. And spelling mistakes can take your score down. And obviously when you know the right answer you would not want to lose your marks because of such a silly reason. Hence, it’s always advisable to cross-check answers and spelling at the end before you submit the paper.