The US Geological Survey wants to map every human-made structure in the United States, and it is asking volunteers to help.
Cassie Tammy Wang and Ashish D’Souza are just two of the many volunteer map editors who ______ to the project since it
began in 2012.
contribute
will contribute
have contributed
will be contributing
Choice C is the best answer. The convention being tested is the use of verbs to express tense in a sentence. In this choice,
the present perfect tense verb “have contributed,” used in conjunction with the phrase “since it began in 2012,” correctly
indicates that map editors have contributed in the past and continue to do so in the present.
Choice A is incorrect because the present tense verb “contribute” is inconsistent with the phrase “since it began in 2012,”
which suggests that the contributions occurred in the past and continue into the present. Choice B is incorrect because the
future tense verb “will contribute” is inconsistent with the phrase “since it began in 2012,” which suggests that the
contributions occurred in the past and continue into the present. Choice D is incorrect because the future tense verb “will be
contributing” is inconsistent with the phrase “since it began in 2012,” which suggests that the contributions occurred in the
past and continue into the present.