not many years ago,some farmers ____

not many years ago,some farmers ____
Not many years ago,some farmers were worryingbecause hawks were taking many of their chickens这里我查了网上文中用were worried,但我们做练习时答案上是给的worried而排除了were worried,.下面还有一个空,they had a new______.网上文章给的worry,但我们答案给的problem,排除了worry?