Structure noun clause basic

Today, the true story of ........... at Little Bighorn remains a mystery.

• happened

• it happened

• what happened

• what happening

For more than a decade, ............. that certain species are becoming scarce.

• the warnings of bird-watchers

• warn the bird-watchers

• bird-watchers have warned

• a warning for bird-watchers

Early in the eighteenth century, Halley accurately predicted when ............. of 1682 would return.

• the comet

• was the comet

• the comet was

• had the comet

No single factor explains why .............. vary so greatly among individuals.

• aging affects

• the effects of aging

• aging has an effect

• the aging effect

Lack of clarity about ............... the party in the coming year will be removed at the party's convention.

• will lead

• lead

• they will lead

• who will lead

We do not ................ the bow drill was first developed for woodworking or fire making.

• whether it

• know whether it

• know whether

• sure whether

Minute Man National Historical Park is a monument to where .............

• the beginning of the Revolutionary War

• in the beginning of the Revolutionary War

• the Revolutionary War to begin

• the Revolutionary War began

Tests on the colors of cars were conducted at the University of California to determine .............. the safest colors for cars.

• which

• which were

• if

• how were

The National Institute of Dental Research estimates .......... in fluoridated areas have about 25 percent less tooth decay than children elsewhere.

• for school children

• school children's

• that school children

• that for school children

The process of photosynthesis explains how ............. able to use the energy in sunlight to manufacture foods from the simple chemicals in air and water.

• green plants

• green plants are

• planting greens

• with green plants are