.Mary is so wet. She _______ in the rain.

---Someone’s been here. Who ___ it be? It looks like Helen.---It ___ be Helen.She is ill in hospital.

I don’t think he＿＿＿＿＿＿＿ a new bike. 

It is usually not quite cold in this area in March, but sometimes temperature ____be very low.

His brother met him at the Great Theatre yesterday afternoon, so he ____ have attended your lecture.