Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.

Although pure diamond is colourless and transparent, but when contaminated with other 

material it may appear in various colours, ranging from pastels to opaque.

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

 If he hadn't wasted too much time, he __________ in his examination.   

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

Up to now, they have not made a __________ whether they will go or not.

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.

A number of tourists is going to return the evaluation form distributed by the travel agent.

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

Sarah and I __________ reserved the rooms in the same hotel. She was really surprised to see me there.

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

There are many __________ history books in our library.

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

We should avoid __________ personal questions.

Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs from the other three in the position of primary stress in each of the following questions.