Auxiliary verbs exercise Complete the following sentences using an appropriate auxiliary verb form You have been riding non-stop for hours You ………………… be very tired a) must b) can c) ought She ………………… be about forty a) must b) can c) will I know I left my phone on this table and it is not here now Somebody …………………… it a) must take b) must have taken c) can have taken That ………………… be true She will never something like that a) can’t b) shouldn’t c) shall You …………………… him a fool It really upset him a) shouldn’t call b) shouldn’t have called c) can’t have called The doctor said I ……………… give up smoking a) must b) can c) ought You …………………… nicer to her She really cares for you a) should have been b) must have been c) can have been ……………… you mind standing up for a moment? b) Should b) Would c) Either could be used here That was a bad place to go hiking You ………………… your back a) could have broken b) should have broken c) would have broken 10 ‘Who is at the door?’ ‘It ………………… be the postman.’ a) must b) could c) Either could be used here Answers You have been riding non-stop for hours You must be very tired She must be about forty I know I left my phone on this table and it is not here now Somebody must have taken it That can’t be true She will never something like that You shouldn’t have called him a fool It really upset him The doctor said I must give up smoking You should have been nicer to her She really cares for you Would you mind standing up for a moment? That was a bad place to go hiking You could have broken your back 10 ‘Who is at the door?’ ‘It must / could be the postman.’ (Use must if you are certain that the person at the door is the postman Use could to express possibility.) Stay on top of your writing! Download our grammar guide from www.englishgrammar.org to stay up-to-date Powered by TCPDF (www.tcpdf.org)