[求助]急问0401语法题，请指点

Rolandz7

28. Because its pitch cannot easily be altered, the oboe serves as the standard

         A           B

which by the symphony orchestra is tuned.        easily be 对了吗？

        

33. Taste buds, small sensory organ located on the tongue and palate, recognize four

                     A                                B

primary tastes: sweet, sour, salty and bitter.  这个怎么改啊？

  C                   D

34. Astronauts receive extensive training to prepare themselves both physically and

                 A                      B      C

psychologically for complexity and rigor of a space mission.

                 D

35. By 1900 several prominent technical institutions, including the Massachusetts

                                          A

laceType>InstitutelaceType> of laceName>TechnologylaceName>, fashioned its own educational offerings to meet the

                           B                        C

industrial needs of the United States.      d怎么改啊  its没有错误吗？

  

lf

28, wwhich by ------by  which
33, salty-----salt
35, its---their

以上， 对不对？请大虾定度！谢谢！！

xkfy0521

34 themselves----them