Sentence:  Meanwhile , in Moscow , Khrushchev was <WSD>adding</WSD> his bit to the march of world law by promising to build a bomb with a wallop equal to 100 million tons of TNT , to knock sense into the heads of those backward oafs who can n't see the justice of surrendering West Berlin to communism . 
Meaning of the word marked with <WSD> tags:  make an addition (to); join or combine or unite with others; increase the quality, quantity, size or scope of