Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.
Contact lenses__________of acrylic are more transparent and less fragile than lenses made of glass.
A. Making
B. Made
C. Are made
D. Which made
Đáp án là B.
Rút gọn đại từ quan hệ ở câu bị động, ta dùng V-ed. Câu đầy đủ: Contact lenses which are made of