Vous avez cherché: by surprise (Anglais - Swahili)

then we took them by surprise while they did not perceive.
basi kwa ghafla tukawashika, hali ya kuwa hawajatambua.

the government was caught by surprise and so far has not reacted.
serikali imekamatwa pabaya na mpaka sasa haijaweza kujibu chochote.

a new indian tv talk show titled satyamev jayate (truth alone prevails) premiered on may 6, 2012 and took the nation by surprise.
kipindi kipya cha mazungumzo ya runinga ya india kwa jina satyamev jayate (ukweli pekee utatawala) kilicho peperushwa tarehe 6,mei, 2012 kiliiacha nchi hiyo kwenye hali ya mshangao.

barnyard chorus observes that “rape culture in singapore is a phenomenon that has really caught us by surprise and disturbed us when it finally reared its unabashedly ugly, misogynistic andabhorrent head.”
barnyard chorus anaona kuwa utamaduni wa ubakaji nchini singapore ni jambo ambalo limetukamata kwa mshangao na kutusumbua wakati hatimaye lilipotokeza kichwa chake kisicho na haya, kinachochefua na chenye chuki dhidi ya wanawake.”