$(1)\,\,{{(C{{H}_{3}})}_{3}}\bar{\ddot{C}}$
$(2)\,\,{{(C{{H}_{3}})}_{2}}\bar{\ddot{C}}$
$\,(3)\,\,C{{H}_{3}}\bar{\ddot{C}}{{H}_{2}}$
$(4)\,\,{{C}_{6}}{{H}_{5}}\bar{\ddot{C}}{{H}_{2}}$
$(I)$ $CH_2 = CH - C \equiv CH$
$(II)$ $CH \equiv C - C\equiv CH$
$(III)$ $CH_3 - CH = CH_2$
$(IV) $ $CH_2 = CH - C = CH_2$