Mongolian children learn to ride when they are_______as three

Question 16.Mongolian children learn to ride when they are_______as three years old.

A.    so young                B. younger                  C.as young                  D. younger than

Question 17.On the farm uncle Duong showed us how to__________cucumbers.                                     

A.    picking                  B. pick       C. to pick                     D. picked

Question 18.Does your stereo play music__________than your old one did?.

A. louder                     B.  loudlier                  C.more louder             D.more loudly