用下列方框中所给动词(组)的适当形式填空: (每小题1分，共7分)   
Meat should ____________________ to make dumplings.
The man ___________ president of USA is named Barack Obama.
_____________ the chance, and you will get out of the difficult situation.
___________ to 2016, we are full of confidence, and believe that the future of the company will be brighter with our joining.
The difference in thickness and weight from the earlier version makes the iPad2 more comfortable ___________.
We’d better have the road signs __________________ clearly so that the tourists know in which direction to go.
The workers shall protect the underground and underwater cables when _________ construction.