Some for Somewhat.—“He is some better today.” It is better to say “he is somewhat better.”
Split Infinitive.—To explain, to thank (infinitive). These words should not be separated (split). “Have the goodness to clearly explain,” should be “Have the goodness to explain clearly.”
“I want to personally thank you,” should be “I want to thank you personally.”
Tenses.—In subordinate clauses the tense of the verb is relative to the tense of the principal verb.
“He intended to have done so,” should be “He intended to do so.”
The imperfect tense, I did is used in speaking of events which took place before a time that is past.
The perfect tense, I have done, is used in speaking of events which have been completed before the present time.
Than me.—“He is taller than me.” The word after than should be in the same case with the word before it.
Than him.—“You are stronger than him.” Say “than he.”
That.—See [Relative Pronouns].