Đặt điện áp u   =   120 √ 2   cos ( 100 π t   +   π / 3 )(V) vào hai đầu điện trở có R = 50 Ω . Biểu thức cường độ dòng điện chạy qua điện trở là:

A.  i = 2 , 4 cos 100 πt   A

B.  i = 2 , 4 2 cos ( 100 πt + π 3 )   A

C.  i = 2 , 4 cos ( 100 πt + π 3 )   A

D.  i = 1 , 2 2 cos ( 100 πt + π 3 )   A

selia___________ in a village in africa. her day starts _______ 4 o' clock. she_________ up and she walks three kilometers_______ the river. she collects ________ water, and she carries it back _______ her house. ______ water is very haevy. it isn't clean but there isn't _________ water in their village. selina doen't _____ to school. she can't read or write. she helps her mother ___________________ the house.