Fill in the gaps with the correct Present or Past tense. ( you/watch) the documentery about tigers yet?
2.The dolphins. .(already/disappear) by the time we got to the beach.
3.Dr Mavis. . (research) how dolphins communicate since 2012.
4. the scientists. .(monitor) the pair of golden eagles for three years before their first chick hatched.
5. Jane was upset because she. .(invest) a great deal of time and money in the failed project