I don’t know ____________.
The bell __ the end of the period rang, __our heated discussion.
_______cloning human embryos is not legal in many countries, some scientists are already pushing ahead with research in order to produce a cloned human baby.
________ the programme, they have to stay there for another two weeks.A Not completing B Not completed C Not having completed D Having not completed
When the boss came in, these workers pretended to________ carefully.
People often have this belief ___development is bad for the environment, but this does not have to be true.A which B whose C that D when