Question

the seikan tunnel, completed in 1988, remains the longest undersea tunnel in the world. its construction was crucial to ____ reliable transportation between honshu and hokkaidō.

which choice completes the text so that it conforms to the conventions of standard english?

(a) establish
(b) establishes
(c) establishing
(d) established

botanist nikolai vavilov dedicated his life to ____ the origins of cultivated plants. he also sought to improve agricultural practices to help secure global food supplies and combat famine. he prioritized identifying regions of high crop diversity, ultimately creating one of the most comprehensive seed banks of his time.

which choice completes the text so that it conforms to the conventions of standard english?

(a) understand
(b) understands
(c) understanding
(d) understood

Explanation:

Question 3

The phrase "be crucial to" requires a gerund (verb - ing form) after "to" because "to" here is a preposition, not part of an infinitive. Among the options, "establishing" is the gerund form. Option A is the base form, B is the third - person singular present form, and D is the past - participle form, which do not fit the prepositional phrase structure.

The phrase "dedicate one's life to" has "to" as a preposition, so it needs a gerund (verb - ing form) after it. "Understanding" is the gerund form. Option A is the base form, B is the third - person singular present form, and D is the past - participle form, which are not suitable for this prepositional phrase.

Answer:

C. establishing

Question 9