Live GMAT classes with Target Test Prep start Nov 1 and Nov 21. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 1
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 1 · Josh Braslow
Sun · 1:00 to 4:00 PM ET
Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemand5 seats leftStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

use of auxiliary verb

Expert replies
by Anindya Madhudor » Wed Nov 14, 2012 8:43 pm
Someone please explain the following.

The period when the great painted caves at Lascaux and Altamira were occupied by Upper Paleolithic peoples has been established by carbon dating, but what is much more difficult to determine are the use to which primitive peoples put the caves, the reason for their deterioration, and the meaning of the magnificently depicted animals.

a) has been established by carbon dating, but what is much more difficult to determine are
b) have been established by carbon dating, but what is much more difficult to determine are
c) have been established by carbon dating, but what is much more difficult to determine is
d) has been established by carbon dating, but what is much more difficult to determine is
e) are established by carbon dating, but that which much more difficult to determine is

OA: D
Join the discussion
Source: — Sentence Correction |

by naveenchandra kv » Thu Nov 15, 2012 5:29 am
The period-- is the first subject and singular. So it should be followed by has. Have/are are incorrect here.
but what is much more difficult to determine-- Shows a contrast which cannot be achieved by carbon dating-- singular-- hence use of "is" is correct.

From the above, Eliminate B,C and E for using Have/are
Eliminate A for using are
That leaves us with D-- Correct answer.

Hope it helps.
Join the discussion

by pritish2301 » Sun Nov 18, 2012 2:02 am
Anindya Madhudor wrote:Someone please explain the following.

The period when the great painted caves at Lascaux and Altamira were occupied by Upper Paleolithic peoples has been established by carbon dating, but what is much more difficult to determine are the use to which primitive peoples put the caves, the reason for their deterioration, and the meaning of the magnificently depicted animals.

a) has been established by carbon dating, but what is much more difficult to determine are
b) have been established by carbon dating, but what is much more difficult to determine are
c) have been established by carbon dating, but what is much more difficult to determine is
d) has been established by carbon dating, but what is much more difficult to determine is
e) are established by carbon dating, but that which much more difficult to determine is

OA: D
Check for possible errors in the sentence:
1. peoples has been established
HAS is correct here since we are referring to a singular antecedent "THE PERIOD"
2. is much more difficult to determine are
ARE - incorrect plural verb, subject verb agreement mismatch. So it should be IS

Hence the correct option is 'D'
Join the discussion

by [email protected] » Sun Apr 14, 2013 11:06 pm
Did anyone consider the possibility of a reversal.

Put the subject ahead of the verb.
IT IS TIME TO BEAT THE GMAT

LEARNING, APPLICATION AND TIMING IS THE FACT OF GMAT AND LIFE AS WELL... KEEP PLAYING!!!

Whenever you feel that my post really helped you to learn something new, please press on the 'THANK' button.
Join the discussion