甲同学将耳朵贴在一根长铁管的一端，乙同学在另一端用力敲一下铁管，甲同学能听到（ ）
| A．1次敲击声; | B．2 次敲击声; | C．3 次敲击声; | D．4 次敲击声. |
It is so hot today． Why not swim in the river？
No， we can't swim in the river． Our teachers and parents always warn us ________in the river． It's too dangerous．（ ）
A．to not swimB．swimming
C．not to swimD．not swimming
I'm proud of Ezhou， our homeland． So am I． It is becoming ________．（ ）
A．more and more beautifully
B．more beautiful and beautiful
C．more and more beautiful
D．more beautifully and beautifully
Because of the special situation this year， about ________ of the students in our school ________ having classes on the Internet at home． （ ）
A．two thirds；areB．two third；is
C．second thirds；areD．two thirds；is
________ unusual year 2020 is!
Yeah! The pandemic （大疫情） is a challenge not only to China but also to the world．（ ）
A．WhatB．What anC．What aD．How
This year President Xi Jinping wrote a letter to the young pioneers China to celebrate ________ 70th anniversary（周年纪念日）． （ ）
A．theirB．themC．theirsD．they