控制绝症(controlling cancr)thr ar two main causs of cancr: hrdity and nvironmnt. w can do nothing to chang our hrdity, that is, th basic physical charactristics that wr passd on to us by our parnts. howvr, w can do a grat dal to control our nvironmnt, which may account for 80-90 %of all cancrs.nvironmntal pollution can b dividd into two kinds: prsonal and imprsonal. prsonal pollution may b dfind roughly as unhalthy habits such as smoking, drinking, and ating th wrong foods. clarly, with nough will powr w can control this prsonal nvironmnt.imprsonal pollution, on th othr hand, rfrs to thos things which ar byond our individual control. on xampl would b industrial pollution, which is vry hard to control bcaus of th xpns involvd.it would b xpnsiv in trms of profits and prhaps jobs. th amrican automobil industry, for xampl, rsistd th law rquiring smog-control dvics bcaus it fard th addd xpns would rduc profits. nvrthlss, som laws protcting th nvironmnt hav bn quit succssful in rducing pollution.