A. offer B. equip C. help D. provide
A. HS->next=s; B. s→next=HS→next;HS→next=s; C. s->next=HS;HS=s; D. s→next=HS;HS=HS→next;
A. for B. with C. to D. without
A. evidences B. pictures C. traces D. hints
A. realm B. net C. relation D. web