Let's look closely at the sentence you wrote about herons and check the grammar step by step:
Your sentence: Herons look for frogs, fish and bugs in shallow water. They stand very still and, once they spot their food, they slowly move closer and snatch it quickly with their beak.
Here are some grammar checks and improvements:
- When listing items like frogs, fish, and bugs, it's good to include a comma before the word 'and' (called the Oxford comma) to avoid confusion. So write: frogs, fish, and bugs.
- The phrase very still is correct and means the herons do not move much.
- After the word and, you put a comma: and, once they spot their food, which is correct because it sets off the phrase once they spot their food to explain when they move closer.
- The verb tenses are consistent: look, stand, spot, move, snatch all make sense in the present tense.
- Lastly, the sentence ends clearly and no punctuation is missing.
Here is a slightly improved and grammatically correct version of your sentence:
Herons look for frogs, fish, and bugs in shallow water. They stand very still and, once they spot their food, they slowly move closer and snatch it quickly with their beak.
Great job! Your sentence was mostly correct. Just remember to put a comma before the last item in a list (the Oxford comma) to make your writing clearer.