TOEFL Practice Test B – Section 2 (Structure)

The ponderosa pine is _____ of the most of the timber used by forest-product firms in the Black Hills of South Dakota.

• the source

• as source

• the source which

• because the source

Answer explanation

The correct choice is 'the source' because it accurately completes the sentence, indicating that the ponderosa pine is the primary origin of the timber used by forest-product firms in the Black Hills.

Computers that once took up entire rooms are now _____ to put on desktops and into wristwatches.

• small enough

• smaller than

• so small

• as small as

Answer explanation

The phrase 'small enough' correctly indicates that computers have been miniaturized to a size suitable for desktops and wristwatches, fitting the context of the sentence. Other options do not convey this suitability.

According to some educators, the goal of teaching is to help students learn what _____ to know to live a well-adjusted and successful life.

• do they need

• they need

• they are needed

• as they may need

Answer explanation

The correct choice is 'they need' because it directly addresses what students must learn to lead a successful life. The other options are grammatically incorrect or do not convey the intended meaning.

The sapphire’s transparency to ultraviolet and infrared radiation makes _____ in optical instruments.

• it is of use

• it uses

• it a useful

• it useful

Answer explanation

The correct choice is 'it useful' because it correctly completes the sentence, indicating that the sapphire's properties make it beneficial in optical instruments.

_____ initial recognition while still quite young.

• Most famous scientists achieve

• That most famous scientists achieved

• Most famous scientists who achieved

• For most famous scientists to achieve

Answer explanation

The correct choice is 'Most famous scientists achieve' because it directly fits the sentence structure, indicating that these scientists attain initial recognition at a young age without unnecessary complexity.

Mango trees, _____ densely covered with glossy leaves and bear small fragrant flowers, grow rapidly and can attain heights of up to 90 feet.

• whose

• which are

• are when

• which

Answer explanation

The correct choice is 'which are' because it introduces a non-restrictive clause that describes the mango trees. It effectively connects the description of the trees being densely covered with leaves and bearing flowers.

_____, the Canadian composer Barbara Pentland wrote four symphonies, three concertos, and an opera, among other works.

• An artist who, prolific

• Is a prolific artist

• Prolific an artist

• A prolific artist

Answer explanation

The correct choice is 'A prolific artist' because it properly describes Barbara Pentland as someone who is highly productive in her musical compositions, fitting grammatically and contextually in the sentence.

The Chisos Mountains in Big Bend National park in Texas were created by volcanic eruptions that occurred _____.

• the area in which dinosaurs roamed

• when dinosaurs roamed the area

• did dinosaurs roam the area

• dinosaurs roaming the area

Answer explanation

The correct choice, 'when dinosaurs roamed the area', indicates the time period during which the volcanic eruptions that formed the Chisos Mountains occurred, aligning with the existence of dinosaurs.

In bas-relief sculpture, a design projects very slightly from its background, _____ some coins.

• as on

• because

• the way that

• similarly

Answer explanation

The phrase 'as on' correctly compares the slight projection of bas-relief sculpture to that of coins, indicating a similar characteristic. The other options do not fit the context of comparison as effectively.

Alaska found the first years of its statehood costly because it had to take over the expense of services _____ previously by the federal government.

• to provide

• be provided

• providing

• provided

Answer explanation

The correct choice is 'provided' because it indicates that the services were already given by the federal government before Alaska became a state. The other options do not fit grammatically in this context.