Wordly Wise 9E

The hot-air balloon is heated. This makes it less ​ (a)   than the surrounding cooler air and causes the balloon to rise.

• dense
• ascending
• significant
• soar
• accomplishing
• flimsy

In 1783 a large crowd assembled to watch the Montgolfier brothers' hot-air balloon. Among the ​ (a)   were members of the French royal family.

• ascending
• significant
• soar
• accomplishing
• flimsy
• spectators
• unwielding
• dense
• experimenting

The Montgolfier brothers' hot-air balloon reached a height of 1,500 feet. Its flight​ (a)   after it had been in the air for eight minutes.

• significant
• soar
• accomplishing
• flimsy
• unwielding
• dense
• experimenting
• soared

Unlike a kite, the Montgolfier brothers' hot-air balloon was not attached to the ground. People watched in amazement as the balloon ​ (a)   to a great height.

• significant
• soar
• suspended
• flimsy
• unwielding
• dense
• mimiced
• ascended
• spectators
• terminate

A sheep, a duck, and a rooster were the first airborne creatures. Two months later, the first human flight in a balloon took place, a truly ​ (a)   act.

• significant
• soar
• suspended
• flimsy
• unwielding
• dense
• mimiced
• spectators
• terminate
• lumbering

By 1900, there was great competition to build a successful heavier-than-air flying machine. The first to ​ (a)   this goal would be famous.

• soar
• suspended
• flimsy
• unwielding
• dense
• mimiced
• spectators
• terminate
• lumbering
• accomplish

The Wright brothers made and repaired bicycles for a living. They ​ (a)   their work on bicycles to concentrate on building a heavier-than-air flying machine.

• soar
• suspended
• flimsy
• unwielding
• dense
• mimicked
• spectators
• terminated
• lumbering

Some early aircraft had as many as six wings, staked above each other. Such airplanes were too ​ (a)   to ever get off the ground.

• soar
• suspended
• flimsy
• unwielding
• dense
• spectators
• terminate
• lumbering
• ascending
• mimicking

Modern aircraft have rigid wings. Early attempts to ​ (a)   the flapping of birds' wings ended in failure.

• soar
• suspended
• flimsy
• unwielding
• spectators
• terminate
• lumbering
• ascending
• accomplish
• mimic

The first aircraft designers had a problem in trying to reduce the plane's weight. The lighter the aircraft, the more ​ (a)   it was.

• soar
• suspended
• flimsy
• unwielding
• spectators
• terminate
• lumbering
• ascending
• accomplish
• dense