Which word fits these sentences?

A Persian rug with beautiful patterns lay/laid on the floor.

I think lay for present tense?

The temperature has raised/risen four degrees in the past hour.

I think risen because there is no object?

I agree.

One more...

After the ceremony, the queen lay/laid her crown in its glass case.

I think laid for past tense.

Right.

You're on the right track! Let me clarify the correct usage of the words in these sentences.

For the first sentence, "A Persian rug with beautiful patterns ________ on the floor," the correct word is "lay." In this case, "lay" is the past tense form of the verb "lie." "Lie" means to rest or recline, while "lay" means to place or put something down. Since the sentence describes an action happening in the past, "lay" is the appropriate choice.

However, in the present tense, you would use "lie" instead. For example, "A Persian rug with beautiful patterns ________ on the floor." Here, the correct word is "lies," as it describes the rug's current state of resting on the floor.

For the second sentence, "The temperature has ________ four degrees in the past hour," the correct word is "risen." You are correct that "risen" should be used because there is no direct object being affected by the action. "Rise" refers to movement or an increase in level or amount, whereas "raise" means to lift or elevate something.

To determine the correct usage in similar situations, you can consider whether there is an object receiving the action. If there is no direct object, use "rise" or "risen." If there is an object that is being affected, use "raise" or "raised."

Remember, context is also crucial in selecting the right word, so consider the tense, subject, and overall meaning of the sentence to make the appropriate choice.