Active-Passive

Closed plane figures like the square or the equilateral triangle can be grouped into a class __ polygons

• called

• to call

• is called

• calls

Experiments in the photography of moving objects _ in both the United States and Europe well before 1900.

• have been conducting

• were conducting

• had been conducted

• being conducted

The values of a people, their customs, and their perceptions of the world _ their language.

• are influenced

• be influenced

• influencing

• influence

Desert animals _ a means of retaining moisture in such a hot, dry climate if they are to survive.

• need

• needing

• to need

• was needed

Ground plans and contour maps of the Earth _ from aerial photographs.

• can be drawn

• can draw

• to draw

• drawn

The operetta first _ as a popular form of musical theater in the nineteenth century.

• to emerge

• emerging

• has emerged

• emerged

___ raw materials into useful products is called manufacturing.

• Transform

• Transforming

• Being transformed

• When transforming

Orchestral instruments _ under the following types: strings, woodwind, brass, and percussion.

• grouped

• can group

• can be grouped

• to be grouped

Amplifiers such as those in computers and sound–reproducing systems are responsible for _ an erratic input signal.

• strengthening

• being strengthened

• strengthen

• to strengthen

___ time and labor, cartoonists generally draw the hands of their characters with only three fingers and a thumb.

• Saved

• Saves

• To save

• The saving