A.termination
B.popularity
C.division
D.commencement

A.friends
B.teenage users
C.their teammates
D.online-only friends

A.Most teenagers use video chat and text messages to maintain a relationship with friends.
B.New forms of communication make a huge contribution in keeping friendships.
C.Teens only encounter in real life a part of their online friends they have made.
D.According to the survey, more than half of teens have ever made new friends online.

A.27 percent
B.57 percent
C.7 percent
D.23 percent

A.As long as she had revised her lesson, she could finish the test today.
B.Without revising her lesson yesterday, she could finish the test today.
C.If she had revised her lesson yesterday, she could finish the test today.
D.She wished she had revised her lesson yesterday, so she can't finish the test today.

A.Tập đoàn kinh tế
B.Doanh nghiệp tự thành lập
C.Doanh nghiệp Tư nhân
D.Trường Đại học, Cao đẳng

A.\(h = \dfrac{{a\sqrt 3 }}{2}\)
B.\(h = \dfrac{{a\sqrt 2 }}{2}\)
C.\(h = \dfrac{{a\sqrt 3 }}{3}\)
D.\(h = \dfrac{{a\sqrt 2 }}{3}\)

A.\(2\sqrt 3 \,\,\left( {cm} \right)\)
B.\(\sqrt {13} \,\,\left( {cm} \right)\)
C.\(\sqrt {14} \,\,\left( {cm} \right)\)
D.\(\sqrt {15} \,\,\left( {cm} \right)\)

A.Độ dài trung đoạn: \(\sqrt {14} \left( {cm} \right)\); Chiều cao: \(3\sqrt 2 \left( {cm} \right)\)
B.Độ dài trung đoạn: \(3\sqrt 2 \left( {cm} \right)\); Chiều cao: \(2\sqrt 2 \left( {cm} \right)\)
C.Độ dài trung đoạn: \(\sqrt {14} \left( {cm} \right)\); Chiều cao: \(2\sqrt 2 \left( {cm} \right)\)
D.Độ dài trung đoạn: \(\sqrt {15} \left( {cm} \right)\); Chiều cao: \(3\sqrt 2 \left( {cm} \right)\)

A.b) \(\dfrac{{a\sqrt 6 }}{3}\)
B.b) \(\dfrac{{a\sqrt 3 }}{3}\)
C.b) \(\dfrac{{a\sqrt 6 }}{6}\)
D.b) \(\dfrac{{a\sqrt 2 }}{2}\)