Cặp chất nào sau đây gây nên tính cứng vĩnh cửu của nước?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

Wehave conductedexhaustingresearch into the effects of smartphones on students'behaviourand theiracademicperformance.

In the past, peopledon't tendto pay muchattentionto leisure time activities, whichisverydifferentfrom now.

Manyliving organisms depend largelyonthe environment for thesatisfactionofitsneeds.

He's a very good worker but he's sometimes a bitslow on the uptake. You have to explain everything twice.