A look at recent trends in world fisheries reveals ________ the ocean on a global scale

31．The foreign visitors were filled with joy when they_____ foot_____ Chinese soil.

Einstein was famous _________ a scientist_________ his Theory of Relativity

Most birds find it safe to sleep in the trees, but ______ they have eggs or young chicks, they don’t use a nest

All the students are here _______ Tom, he is ill in hospital.