Câu hỏi: Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction m each of the following questions.
The number of protons in the nucleus of an atom vary from element to element
A. of
B. an
C. vary
D. to
The number of protons in the nucleus of an atom vary from element to element
A. of
B. an
C. vary
D. to
varies - the number of. .. theo sau bởi động từ số ít
Đáp án C.