This sentence has a problem with verb tense. Since the first part of the sentence, "After the canoe flipped over and the provisions were lost," uses two past-tense verbs ("flipped" and "were"), the rest of the sentence needs to be in past tense too, since it is describing events that took place at the same time as those described earlier in the sentence. "Are declaring" is in the present progressive tense, so it contains the sentence's error. You could correct the sentence by changing "are declaring" to "declared," yielding the sentence, "After the canoe flipped over and the provisions were lost, the campers declared the trip a disaster."

This sentence uses the gerund "approaching" when the noun "approach" already exists. Changing "approaching" to "approach" clarifies the sentence. The corrected sentence reads, "It can be difficult to hear the approach of cars running on electric engines."

The timeline of verb tenses in this sentence doesn’t quite make sense. Read it out loud and you will probably hear that something is wrong. Since the first half is in the past, the second half should be too. The corrected sentence reads: After attending a workshop on cake decorating, Joe has brought edible works of art to every family gathering.

The correct verb tense would be "make," since the sentence is phrased as a question and is not a declarative statement about something in the past.

“Have chose” should be written as “have chosen.” The past participle of “to choose” is irregular.

This sentence has a problem with the timeline of verb tenses. Since the first half of the sentence is in the past, the second half has to be too. The corrected sentence reads, "As soon as I bought an expensive patio umbrella I found them on clearance everywhere."

This sentence has a problem with verb tenses. Since the first half of the sentence is in the past, the second half has to be too. The corrected sentence reads, "They puzzled over the little mysteries of life and language, wondering if it was possible to mingle in a group of two."

The timeline of this sentence isn’t quite right. Read it out loud, and you will probably hear that something is funny with the verb tense. Since the first half is in the past, the second half has to acknowledge that. The corrected sentence reads: Since he finally quit his stressful job, Joe has been full of energy and witty banter.

This sentence does not maintain a logical timeline between verb tenses. Read it out loud, and it will probably sound funny. “Had never encountered” should be used following a sentence in the past, not the present. The corrected sentence reads: Harold almost never complains, but he has never encountered customer service this lousy before.

This sentence uses the incorrect tense of the verb “to be.” The corrected sentence reads: Scientists debate whether the primary reason for the extinction of the prehistoric wooly mammoth was overhunting by humans or climate change.