Mywalletisnowheretobefound.I_____itwhenIwasonthebus.
D
must have+done 用于推断过去某个时间肯定发生了的事情。
Beingextremely_____tothecold,Idonotlikeskating.
Copernicusmaintainedthattheearth_____roundthesun.
_____hespeakssoftlyisnoproofthatheiskind.
Yourbikeneeds_____.You‘dbetterdoirightnow.
Thereisn‘tmuchmilk_____isleftinthebottle.