Spot the error and rewrite the correct sentence :
He prescribe medicine alongwith a few exercises to his patients.
The errors in the given sentence are:
1. "prescribe" should be "prescribes" to match the singular subject "He".
2. "alongwith" should be "along with", as "alongwith" is incorrect usage in English.
Corrected Sentence: He prescribes medicine along with a few exercises to his patients.
Identify the part of the sentence that contains a grammatical error:
Each of the boys have submitted their assignment on time.