I couldn't imagine ______difficult it was for these badly injured victims to make it to the hospital.
—Under no circumstances ________ the door to the Data Centre unlocked. —I promise I'll be more careful in future.
The drug used to treat this disease causes bad side effects, some of which ________ deadly.
.No sooner ________ down on bed ________ the telephone rang.
________ about wild plants that they decided to make a trip to Madagascar for further research.
Fighting an artificial greenhouse effect seems to be the greatest of environmental challenges, ________?