A.Had you paid enough attention, you wouldn't have asked such a question now.
B.Had it not been for your attention, you wouldn't ask such a question now.
C.Had you not paid enough attention, you wouldn't ask such a question now.
D.Had it not been for your inattention, you wouldn't ask such a question now.

A.Had you paid enough attention, you wouldn't have asked such a question now.
B.Had it not been for your attention, you wouldn't ask such a question now.
C.Had you not paid enough attention, you wouldn't ask such a question now.
D.Had it not been for your inattention, you wouldn't ask such a question now.

A.success
B.access
C.problem
D.culture

A.cùng pha.
B.lệch pha \(\dfrac{\pi }{3}\).
C.vuông pha.
D.ngược pha.

A.1 m/s.
B.0,25 m/s.
C.2,5 m/s.
D.0,1 m/s.

A.proton.
B.photon.
C.electron.
D.notron.

A.một phần tư chu kì.
B.một chu kì.
C.hai chu kì.
D.một nửa chu kì.

A.\(mg\alpha \).
B.\( - mgl\alpha \).
C.\(\dfrac{1}{2}mg\alpha \).
D.\( - mg\alpha \).

A.Tia tử ngoại.
B.Tia hồng ngoại.
C.Tia X.
D.Sóng siêu âm.

A.tỉ lệ nghịch với r.
B.tỉ lệ thuận với r2.
C.tỉ lệ nghịch với r2.
D.tỉ lệ thuận với r.