Công thức phân tử của hợp chất khí tạo bởi nguyên tố R và hiđro là RH₃. Trong oxit mà R có hoá trị cao nhất thì oxi chiếm 74,07% về khối lượng. Nguyên tố R là :

Choose the best answer for the following sentence:

We are enjoying our holiday. We _________ a nice room in the hotel.
 

Choose the best answer for the following sentence:

Be careful with ___________ computer games. You may not control yourself.

Choose the best answer for the following sentence:

Her aunt feeds her but who is in charge of paying her ___________?
 

Choose the best answer for the following sentence:

The function of ROM in computer is to provide information that is ___________ and permanent.
 

Choose the best answer for the following sentence:

Every two days my mother buys a ___________ of bananas for our desert.
 

Choose the best answer for the following sentence:

Nam: “Why do we use T.V _________?''

Tuan: “To watch news, performances, football matches, and to learn foreign languages”

Choose the best answer for the following sentence:

 An architect is a person __________ profession is planning or designing of buildings.
 

Choose the best answer for the following sentence:

Speaking test can be called as __________ test.
 

Choose the best answer for the following sentence:

Reading books takes times away __________ watching films or playing games.

Choose the best answer for the following sentence:

Internet increases the popularity __________ shopping at home.