$a. \sin x+\cos x=1$	$d. \frac{1}{\sin 2x}+\frac{1}{\cos 2x}=\frac{2}{\sin 4x}$
$b. \sqrt{3}\sin 3x+\cos 3x+1=0$	$e. {{\left( \sin \frac{x}{2}+\cos \frac{x}{2} \right)}^{2}}+\sqrt{3}\cos x=2$
$c. 2\sqrt{2}\left( \sin x+\cos x \right).\cos x=3+\cos 2x$	$f. \sin x+\sqrt{3}\cos x=\sqrt{2}$

$a.4\left\| \cos x \right\|-\sqrt{3}=\sqrt{3}$ trên khoảng $\left( 0,2\pi \right)$

$a.4\left\| \cos x \right\|-\sqrt{3}=\sqrt{3}$ trên khoảng $\left( 0,2\pi \right)$	$d. \left\| \cos \left( x+\frac{\pi }{4} \right) \right\|=2$ trên khoảng $\left( -\pi ,\pi \right)$
$b. 6\left\| \cot x \right\|+6=0$ trên khoảng $\left( -\pi ,\pi \right)$	$e. 2\left\| \tan x \right\|-2=0$ trên khoảng $\left( 0,2\pi \right)$
$c. 2\left\| \sin x \right\|+1=2$ trên khoảng $\left( -\pi ,2\pi \right)$	$f. \left\| \cot x \right\|=1$ trên khoảng $\left( 0,2\pi \right)$

__1. ________ -ment/ -ion	_15_________ a living	____28______ an excuse
___2. _______ assignment	16__________ progress	_____29_____ use of
3. __________ course	17__________ exercise	30 __________ sports
__4.________ research	_18_________ a service	___31_______ V-ing (shopping)
____5______ work/ a job	__19________ a mistake/ an error	__32________ a fuss
_____6_____ chores	___20_______ an interview	_33_________ a project
7__________ a journey	21__________ money/ profit/ a fortune	34 __________ jokes
8__________ good/ harm/ a favour/ wonders/ damage	22__________ a service	35__________ a mess
9__________ an apology	23__________ an effort/ attempt	_36_________ room for
_10_________ fun of sb	__24________ a list	___37_______ a choice
__11________ a difference	__25________ the/ one’s bed	___38_______ one’s hair/ teeth
12__________ tricks	26 __________ love/ war/ peace	39 __________ a test/ an exam
13__________ an offer	27__________ business	_40_________ breakfast/ lunch
14__________ a speech