1.The spacecraft is traveling 50 times as faster than the speed of a pistol bullet.

     A                                                                        B                   C         D
PEMBAHASAN:The correct form for making this comparison is “as fast as.”
2.The traveler can to teach some of the villages along the Amazon only by riverboat.
                                        A                                 B                                            C                 D
PEMBAHASAN:The infinitive with “to” canot follow the modal”can.”The correct form is”can reach.”

3.Natural predators,disturbing from tourists,and pollution have all contributed to the decline 
                                             A                                                               B                    C                          D
of the California Condor.

PEMBAHASAN:The noun “predators”and “pollution”are used as subjects.therefore,the word”disturbing”needs to be in the noun form”disturbances”to be a parth of the parallel subject.

4.Today the number of people which enjoy winter sports is almost double that of twenty years 
                          A                                                                       C                               D

PEMBAHASAN:The relative pronoun “which” refers to things,not people.”Who”should be used to refer to people.

5.The soay sheep,the old breed of sheep in existence,has changed little since 3500 B.C.
                                         A                                           B                  C                       D
PEMBAHASAN:The superlative form”oldest”should be used because soay  are being compared toall other breeds of sheep.

6.Voyager 2 is a spacecraft which has greatly expanded ours knowledge of the solar system.
                                                       A               B                             C                        D
PEMBAHASAN:The pronoun “ours”cannot be used in an adjective position.”Ours” is the correct possessive to use before a noun.

7.Dolphins,whales,and many others sea creatures use highly sophisticated navigation systems.
                                              A         B                                          C                                                          D
PEMBAHASAN:The pronoun”others” cannot be used before a noun.”Other”is the correct adjedtive to use.

8.The smallest things in the universe are,paradoxically,be explored by the largest machines.
                  A                         B                                                              C            D
PEMBAHASAN:The verb form”be” cannot follow the aux-word”are.””Are(being)explored”is the correct form.
9.Fiber is a important element in nutrition,and it aids in protecting the digestive tract as well.
                               B                                                 C                                             D
PEMBAHASAN: The article”an”should be used before a vowel sound.
10.Copper is a metal which is easy worked and which mixes well with other metals to form 
                                            A          B                                          C                          D

PEMBAHASAN:The adjective”easy”cannot modify the verb”worked.”The adverb form”easily”should be used to indicate”how”metal is worked.

reference:Canbridge preparation for the toefl test.
Thank for reading trik jitu mengerjakan soal toefl in my blog.