II. Construct proofs for the following more challenging problems, justifying each step that is not a premise. 1) (FG)H,(FH)&(HT),TW,W&S/:GSS 2) (BC)A,A(ST),B&S,(T&A)(WS)/:., 3) (XY)(YZ),X&( YY),ZZ:.YZ 4) (AB)(CD),(FA)(AB),A(FA),A&C/DF 5) (AB)(CD),CA,(A&F),F/:D 6) (AB)(CD),(CW)&( DA),A&W/:(XY) 7) A(BE),E(DH),F,DF/:AB 8) DB,CB,DC/:DC 9) (AB)C,AF,F(D&E),(DH),(EH)/:C 10) (A(BT)), (A & C) (ZD),(PT)D,P(T&S)/Z.