94. The doctor warned everyone not to drink the water without first boiling it.

• The correct option is B. not to drink - boiling. This is the correct infinitive construction after "warned".

95. Most people talk too much and don't realize how important listening is.

• The correct option is D. listening. This is the correct gerund form after "realize".

96. If you've finished the dictionary, I'd like to borrow it.

• The correct option is C. using - to borrow. This is the correct infinitive construction after "like".

97. Smokers generally know that smoking is extremely harmful, but they can't help doing it.

• The correct option is A. doing. This is the correct gerund form after "can't help".

98. The tooth had been causing me so much pain that at last I went to see my dentist and have it pulled out.

• The correct option is D. to see. This is the correct infinitive construction after "went".

99. The mountaineers who had been trapped by the avalanche were very lucky to have been found by the rescue team within an hour.

• The correct option is C. to have been found. This is the correct perfect infinitive construction after "were lucky".

100. The plan hadn't been prepared carefully enough for all the details to be taken into consideration, so the boss asked to have it redone.

• The correct option is A. to have taken - redone. This is the correct perfect infinitive construction after "asked".

101. Grandpa seems to have lost his glasses, and I don't think he will be able to find them without our help.

• The correct option is A. to have lost. This is the correct perfect infinitive construction after "seems".