So biologists were ________ early this year when with the help of the Navy, they were able to ________ a particular blue whale for 43 days, monitoring its sounds．A.delighting：keep track ofB.delighted：keep in touch ofC.delighting：keep an eye outD.delighted：keep track of
网友回答
D解析delighting意为“让……高兴的”，delighted意为“某人感到高兴的”：说明人的用delighted：keep track of“跟踪”。