shoot/shoot at

[loysten8]

shoot:
I shoot the pheasants on the farmer's land.

shoot at:
I shoot at the pheasants on the farmers'land.

with the use of "at", it means what difference from the one without "at"?

by the way, "I knows everything about computer" sounds natural? or "all about computer"

 

[Barb_D]

If you shoot "at" something, you may or may not hit it.

 

[emsr2d2]

shoot:
I shoot the pheasants on the farmer's land.

shoot at:
I shoot at the pheasants on the farmers'land.

with the use of "at", it means what difference from the one without "at"?

by the way, "I knows everything about computer" sounds natural? or "all about computer"

As Barb explained, "to shoot at" doesn't necessarily mean you were successful. "I shoot pheasants......" would suggest that you actually did hit/kill them.

"I've been shot" and "I've been shot at" would have two very different meanings!

Your second question - I'm sure it was a simply typing error when you typed "I knows" instead of "I know"! In my opinion, a better sentence would be "I know everything about computers".