选择题：I() ping－pang quite well, but I haven t had time to play since the new year.

He is intelligent enough, but he lacks () for working hard and becoming a successful person.

You () such a stupid mistake if you had followed my advice.

Someone who is () is eager to visit new places and have new experiences.

We () the project on time without your kind assistance.

If there () no air and water, all living creatures would die.