. It never occurred to humans until the mid-l990s _______some animals can be cloned.
Only when to explain thereasonfor this.
Large earthquakes __________ the ocean can create a series of huge, destructive waves called tsunamis that flood coasts for many miles.
He is so addicted to smoking that ________ seems to be no chance of talking him into quitting.
--- He is a very hard-working student. ---________.As far as I know, he often burns the midnight oil.
---Has anything caught your eye in today’s newspaper? ---Yes. A new eight-kilometer-long road is under ________ that links the port area with the motorway system.