Some families have long histories ____ others know very little about their ancestors.

Some families have long histories, ____ others know little about their ancestors.

People with no family history of cancer are unlikely to develop cancer.A．RightB．WrongC．Not

Some families have long histories, ______others know very little about their ancestors.A．b

In the long history of natural evolution,many kinds of animals have______from the earth.A．

People with no family history of cancer are unlik

China is a country that has a long history.China is a country ______ a long history.