1. Nam…………………. swimming twice a week.
A. is going often B. is often going
C. often goes D. goes often
2. I think the weather………………….be bad tomorrow.
A. shall B. Will C. is going D. could
3. He……here a few minutes ago.
A. comes B. Came C. has come D. come
4. Be quiet! The students…………………...
Tìm Min của A=\frac{\sqrt{x}}{\sqrt{y}+\sqrt{z}}+\frac{\sqrt{y}}{\sqrt{x}+\sqrt{z}}+\frac{\sqrt{z}}{\sqrt{y}+\sqrt{x}}
B=\frac{x^{2}}{y^{2}}+\frac{y^{2}}{x^{2}}-3(\frac{x}{y}+\frac{y}{x})+4 (x,y> 0)...