Sam can't afford the camera he craves because it's too expensive.

He was busy writing that story all morning, only stopping for a cup of tea occasionally.

He has been busy writing this story all morning, only occasionally stopping for a cup of tea.

He is the son of a rich family, but he seems to be down and out.

He is the son of a rich family, but he seems to be down and out.

He often takes advantage of her lack of business acumen to cheat her.

He often takes advantage of her lack of business sense to cheat her.

Professor Wang, would you do us the honor of attending our English evening on Saturday?

Professor Wang, would you do us the honor of attending our English evening on Saturday?

From his appearance, he doesn't look like an old man in his eighties at all.

Considering his appearance, he seems not to be an old man in his eighties.

7) They certainly don't intend to train him as an engineer, and I guess they will never do so.

There is no doubt that they have no intention of training him as an engineer, and I doubt that they will ever.

I doubt that this factory has any quality control. After a week's observation, I found that this is indeed the case.

I doubt that there is any quality control in the factory. After a week's observation, I found that this is indeed the case.