NYLON ……… IN 1930S.A. INVENTED B. IS INVENTED C. WAS INVENTED D. HA...

6. - BÀI GIẢNG HSG HUYỆN ANH 19
BÀI GIẢNG HSG HUYỆN ANH 19

6. Nylon ……… in 1930s.

a. invented b. is invented c. was invented d. has been

invented