We have little___information about developments in this field.

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

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

Scientists now have some surprising answers about whether brain power______as we get older

Its already dark now. Dont you think its about time______？A．we are having dinnerB．we have

We may not be able to _____ the information that we have _____.A.remember ⋯recalledB.r

There is very little rain in this region of the country; ______, we often have crop failur