What we know about certain diseases are still not sufficient to prevent them from spreading easily among the population.

Animals like frogs have waterproof skin that prevents it from drying out quickly in air, sun, or wind.

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions. Air pollution became very serious in recent years due to human activity.
A B C D

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions. The president did not sound unduly concerned that the new policy would be disadvantaged to the future development of the company.
A B C D

At the moment, the multinational corporation is in the process of upgrading their departments.

Years ago, mothers often stayed at home and have greater control of children than fathers did.

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.
Students at this school only need to wear her uniforms on Mondays.