Write the $IUPAC$ names of the following compounds:
$(1)$ $CH_3-CH=C(CH_3)_2$
$(2)$ $CH_2=CH-C \equiv C-CH_3$

(N/A) $(1)$ For $CH_3-CH=C(CH_3)_2$,the longest chain contains $4$ carbon atoms. Numbering starts from the right to give the double bond and substituent the lowest possible locants. The $IUPAC$ name is $2-Methylbut-2-ene$.
$(2)$ For $CH_2=CH-C \equiv C-CH_3$,the longest chain contains $5$ carbon atoms. Numbering starts from the left to give the double bond priority over the triple bond when locants are equivalent. The $IUPAC$ name is $Pent-1-en-3-yne$.