Xác định đúng/sai:
41 - 15 = 36
Đúng
Sai
62 - 7 = 55
Đúng
Sai
72 - 33 = 49
Đúng
Sai
A.sai
B.đúng
C.sai
D.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
The scientist said that the identification of these different pollutants and their effects on ecosystems _____ complex.
A.has been
B.was
C.is
D.be

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Peter said that he ………. the web search engine to find information about environmental preservation.
A.has used
B.uses
C.is using
D.had used

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
The environmentalist said that the sources of pollution ……….numerous.
A.will be
B.are
C.were
D.is

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Nam told me that pollution ………. one of the problems in his neigbourhood.
A.was
B.is
C.will be
D.has been

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Molly told the class that we ………. severe environmental pollution.
A.will face
B.were facing
C.have faced
D.are facing

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Peter said that he ………. to New York the following week
A.will fly
B.is going to fly
C.flies
D.was going to fly

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Harry said that WWF ………. the world’s largest independent conservation organization.
A.will be
B.be
C.was
D.has been

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Nam added that the pollutants ………. from natural disasters or the result of human activity.
A.have come
B.can come
C.will come
D.could come

Điền số còn thiếu vào bảng sau:
Số bị trừ
Số trừ
Hiệu
A.44
B.22
C.16
D.54