Cho hàm số f(x) liên tục trên đoạn [a; b] sao cho m ≤ f(x) ≤ M, ∀x ∈ [a; b]. Mệnh đề sai trong các mệnh đề sau là
A. Luôn tồn tại x1 ∈ [a ; b] sao cho f(x) ≥ f(x1), ∀x ∈ [a; b].
B. Luôn tồn tại x2 ∈ [a ; b] sao cho f(x) ≤ f(x2), ∀x ∈ [a; b].
C. Với mọi k ∈ [m ; M], luôn tồn tại c ∈ [a; b] sao cho f(c) = k.
D. Đồ thị của hàm số là một đường liền trên đoạn [a ; b].

A. -∞.
B. +∞.
C. ±∞.
D. Không tồn tại.

A.
B. 1
C. 2
D. +∞

A. 1.
B. 3.
C. 2.
D. 0.

A.
B. 0
C.
D.

Choose one sentence that has the same meaning as the root one:
She had only just put the phone down when her boss rang back.
A. Hardly she had put the phone down when her boss rang back.
B. Hardly she puts the phone down when her boss rang back.
C. Hardly did she put the phone down when her boss rang back.
D. Hardly had she put the phone down when her boss rang back.

Choose one sentence that has the same meaning as the root one:
He was exhausted, but he finished the marathon race.
A. Even though being exhausted, he finished the marathon race.
B. Although exhausted, however he finished the marathon race.
C. In spite of his exhaustion, he finished the marathon race.
D. Despite of the exhaustion, but he finished the marathon race.

Choose one sentence that has the closest meaning to the root one:
"I’m sorry. I can’t help you," Peter said to me.
A. Peter promised to help me.
B. Peter approved of helping me.
C. Peter regretted not to help me. 
D. Peter regretted not helping me.

Choose one sentence that has the same meaning as the root one:
He said that if he had been me he would have applied for a job in the city.
 
 
A. He suggested that we should apply for a job in the city. 
B. He promised to offer me a job in the city. 
C. He advised me to apply for a job in the city. 
D. He told me he would apply for a job in the city.

Choose one sentence that has the same meaning to the root one:
The captain to his men, "Abandon the ship immediately!"
A. The captain invited his men to abandon the ship immediately.
B. The captain suggested his men abandon the ship immediately.
C. The captain ordered his men to abandon the ship immediately.
D. The captain requested his men to abandon the ship immediately.