1. Ever since he was a baby, he suffered from a serious illness.
2. Ever since he was a baby, he has suffered from a serious illness.
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Which one is grammatical? Are both OK? Which one is commonly used? In #1, the present tense is used and in #2, the present perfect tense is used.
Both are OK, but 2 is the grammatically correct sentence.
Both sentences are grammatically correct, but they have slightly different meanings and usage.
Sentence #1: "Ever since he was a baby, he suffered from a serious illness."
This sentence uses simple past tense. It suggests that the person no longer suffers from the illness. It implies that the person's illness started in the past and ended at some point in the past as well. The use of the simple past tense indicates a completed action in the past.
Sentence #2: "Ever since he was a baby, he has suffered from a serious illness."
This sentence uses present perfect tense. It suggests that the person continues to suffer from the illness. It implies that the person's illness started in the past and is ongoing in the present. The present perfect tense is used to indicate actions that started in the past and have a connection or relevance to the present.
In terms of common usage, sentence #2 is more commonly used in this context. It is more natural to use present perfect when describing a condition or situation that started in the past but is still ongoing. However, the choice between simple past and present perfect can depend on the context and the intended meaning.