I remember a ____ famous scientist said that we should believe in ourselves first of all.

There are many people in the park. Some are walking along the lake. _________ are sitting on the grass.

Clearly, in a system ______ every decision is made on the basis of tradition alone, it may be difficult to achieve progress [ ]

This returned Chinese scholar has become one of the top experts in this field.—-Yes,I know him very well.He____in Africa with animals for eight years

Would you like to go shopping with us this afternoon— ________,but I must do my homework first.