... the exam very easily.
19. It was very cold last night, we went out for a walk.
Exercises Unit 9- 10 English 12
20.It was very cold last week, we had to cancel our picnic.
21 .He was an honest man, ... him.
22 .He was an honest man, he was released from prison.
23 .The fight attendant serves dinner, I didn’t eat.
24 .The negative effect of cigarette smoking is enormous, many people still smoke.
25 .Jenny ... Unit 9- 10 English 12
BUT, SO, HOWEVER and THEREFORE
Exercise 1: Add so, but, therefore, however where appropriate.
1. The wind was howling outside,_________it was warm and comfortable indoor.
2. ...
... x
2
= A
2
cos(ωt +φ
2
). Biên độ của dao động tổng hợp là
A. A = A1 + A2 + 2A1A2cos( 2 - φ1). B. A =
)cos (2
122 1
2
2
2
1
ϕϕ
−−+ AAAA
C. A =
)cos (2
122 1
2
2
2
1
ϕϕ
−++
AAAA
. D. A = A1 + A2 ... động tổng hợp là
A.
22 11
22 11
coscos
sinsin
ϕϕ
ϕϕ
ϕ
AA
AA
tg
+
+
=
B.
22 11
22 11
coscos
sin-sin
ϕϕ
ϕϕ
ϕ
AA
AA
tg
+
=
C.
22 11
22 11
cosAcosA
cosA+cosA
=cos
ϕϕ
ϕϕ
ϕ
D.
22 11
22 11
cosA+cosA
sinA+sinA
=sin
ϕϕ
ϕϕ
ϕ
81: ... u
N
= 4cos (
20
9
π
t -
2
9
π
) (cm) B. u
N
= 4cos (
20
9
π
t +
2
9
π
) (cm)
C. u
N
= 4cos (
40
9
π
t -
2
9
π
) (cm) D. u
N
= 4cos (
40
9
π
t +
2
9
π
) (cm)
1 82 : Một sóng cơ...