In the 21st century, all nations must take their ________of responsibility for the global safety.

We forbid ______ in the lecture hall, so you are forbidden _____ here

My mother  _______ a bed in the sitting-room for my cousins from the countryside. 

It suddenly ______ to the detective that the professor was probably murdered by his own wife .

It rained heavily last night. ________, much of the farm and forest land has been destroyed.    (   ).