Access        the mountain-town is often difficult because of the bad roads.

Let’s go to give the stranger a hand.________he’s got into some trouble.

The task given by the boss is ____   done, and we are to sum up our working experienceafter its accomplishment.

 The little boy, out of curiosity, _______ the toy to see how it worked, but couldn’t put it together.

(2010·山东)That's the new machine ________ parts are too small to be seen.