Sentence:  At Geneva in 1954 , to get the war in Indo-China settled , the British and French gave in to Russian and Communist Chinese demands and agreed to the setting up of a Communist state , North Viet Nam - which then , predictably , <WSD>became</WSD> a base for Communist operations against neighboring South Viet Nam and Laos . 
Meaning of the word marked with <WSD> tags:  undergo a change or development