Kim loại nào sau đây là kim loại kiềm thổ? 

A. Ca

B. Fe

C. Na

D. Al

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Please don't_________a word of this to anyone else, it's highly confidential.

A. breathe

B. speak

C. pass

D. mutter

Mark the letter A, B, C, or D on your answer sheet to indicate the word that is closest in meaning to the underlined part in each of the following questions

In most countries, compulsory military service does not apply to women.

A. superior

B. mandatory

C. beneficial

D. constructive