Read the text below. For questions (23–32) choose the correct answer (A, B, C or D)
The Meaning of Monkey Talk
Krak! Hok! Boom! These might sound (23) ______ random noises to us, but to a species of monkey living in Ivory Coast, they (24) ______ a very specific meaning. During (25) ______ studies of the Campbell’s monkeys in the Tai National Park, naturalists (26) ______ that when the monkeys spotted a leopard on the prowl, they would cry "Krak!" to (27) ______ other members of their group of the danger. A hok, by (28) ______ , alerted other monkeys that a crowned eagle was circling overhead. Boom seemed only to indicate that a branch had broken (29) ______ a nearby tree. What particularly intrigued the researchers, however, was the fact that the creatures weren’t just (30) ______ certain sounds to certain events, but seemed to have developed a kind of syntax. Sometimes, for instance, a monkey would add an oo sound to one of the above-mentioned noises, to suggest a(an)(31) ______ but more general threat: so krak-oo would mean that there was danger, but not (32) ______ from a leopard. The language of the Campbell’s monkeys may be "the most complex example of ‘proto-syntax’ in animal communication known to date", the researchers told.
Sometimes, for instance, a monkey would add an oo sound to one of the above-mentioned noises, to suggest a(an) (31) ______ but more general threat: so krak-oo would mean that there was danger...