Life is like the weather．Sometimes it rains but most of the time we have____ (sun)days.

People not only in China but also from many other____ (country)are influenced by Confucius(孔子).

Job said try to do things best try to do things____ (different).

-Many teens spend much time in front of____ (they)smart phones ,computers and TVs -They should cut down screen time.

-Hey,you have so many clocks in your bedroom!Are you crazy or what? -No.I am a heavy____ (sleep).I just want to make sure I can wake up on time.

—Why don't you ask your brother __________ help?    

已知A,B,C三点的坐标分别是A(3,0)，B(0,3)，$C(\cos \alpha ,\sin \alpha )$，$\alpha \in \left(\frac{\pi }{2},\frac{3\pi }{2}\right)$，若$\overrightarrow{AC}·\overrightarrow{BC}=-1$，则$\frac{1+\tan \alpha }{2{\sin }^2\alpha +\sin 2\alpha }$的值为（   ）

下列关于微生物培养和利用的叙述不正确的是