He had his camera ready ____he saw somethingthat would make a good picture．

What on earth are the police busy with— They have been investigating how the train crash __________

The lab is equipped _______________ a lot of modernequipmentformedicalexperiments.[ ]

Our monitor didn’t see all the students, becausewas ill and didn’t come toschool today.

I remember there _____ a lot of fish in Yanglan Lake. Now it has been polluted.–What a pity! I think we should play a role in protecting the environment.