Fill in the Blanks Fill in the Blanks: Modals of Probability B1Online version Test your knowledge of modals of probability with this fill in the blanks game! by Marina Prieto Blázquez 1 was can't couldn't might must could Yesterday , when I find my keys , I thought they be in the living room or have fallen behind the sofa . After searching for a while , I realized they be in my bag because I remember putting them there earlier . I relieved when I found them inside , confirming my earlier assumption . It have been too difficult to locate them , but sometimes small things like keys can create a lot of uncertainty ! 2 can't could they always might chatting must As I was walking to the bus stop this morning , I saw my friend Sarah talking to a stranger . They have met before at a community event , or they be discussing a shared interest . Knowing Sarah's outgoing nature , it be a new acquaintance she's making . She be shy when it comes to making friends . Later , when I asked her about it , she confirmed that had just met and were about their favorite books . It's interesting to speculate about chance meeting !