_________with the size of the whole earth, the biggest ocean does not seembig at all[ ]

When you are learning a foreign language, _______, you must forget your own language

The secretary made a note of it _______ she should forget

Have you been to Hong Kong before ——____, I _____ there in 1997.

Only when _______ in 1941, _______ to get back to his research again. [ ]