Question 47: Mark the letter A, B, C, or D on your answer sheet to indicate the undelined part that needs correction in each of the following questions: The assumption that smoking has bad effects on our health have been proved.
Knowledge: The harmony between subject and verb
assumption (n): assumption
The main subject of the sentence is “assumption”. This is an uncountable noun, so the verb that follows must be conjugated in .
Edit: have been proved => has been proved
=> The assumption that smoking has an adverse effect on our health has been proven.