In Western culture, it is general to exchange cards together with presents by sending a grateful/thankful heart.

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Is the sentence above grammatical? Would you check the ungrammatical parts? Which one is beter of the two, grateful and thankful?

In Western culture, it is general to exchange cards together with presents to express gratitude.

or to express thanks

The sentence "In Western culture, it is general to exchange cards together with presents by sending a grateful/thankful heart" is not grammatically correct. Here's the corrected version:

"In Western culture, it is common to exchange cards along with presents as a way of expressing gratitude."

In this revised sentence, the phrase "sending a grateful/thankful heart" has been replaced with "as a way of expressing gratitude." This makes the sentence more concise and avoids any potential confusion.

Regarding your question about the choice between "grateful" and "thankful," both words can convey a similar meaning in this context. However, "grateful" tends to emphasize feeling appreciative towards someone, while "thankful" emphasizes feeling obliged or indebted to someone. In this case, either word could work depending on the exact sentiment you want to express.