1. He dug at the river bottom.

Question

2. He dug the river bottom.

(Which one is correct?)

3. Hippo dived into the river, but he hit the water too hard.
(What other expressions can we use instead of 'hard'?)

4. Hippo dug and dug.
5. Hippo kept digging.
6. Hippo continued digging.
7. Hippo continued to dig.
8. Hippo dug on and on.
9. Hippo dug continuously.

(Are they all the same in meaning? Thank you for your help.)

Answer 1

1. He dug at the river bottom.
2. He dug the river bottom.

(Which one is correct?) Both could be correct, but in light of the sentences below, I think the first one is what you mean. When you say digging the river bottom, it usually means someone (or a large company) is digging out the river bottom to make it deeper so larger boats and ships can get through. The second one also implies the use of some big dredging machine. " target="_blank">http://en.wikipedia.org/wiki/Dredging

3. Hippo dived into the river, but he hit the water too hard.
(What other expressions can we use instead of 'hard'?)
Is "Hippo" a proper name? Or are you referring to a hippopotamus in general? If it's the latter, then you need to write "A hippo ... " or "The hippo ... "

4. Hippo dug and dug.
5. Hippo kept digging.
6. Hippo continued digging.
7. Hippo continued to dig.
8. Hippo dug on and on.
9. Hippo dug continuously.

All are fine, whether you use the article in front of "hippo" or not.

Answer 2

PS -- "hit the water too hard" is the best expression here. You could also write that he did a belly-flop, but it doesn't mean exactly the same thing. Close, but not exact.

Answer 3

Hippo!!