Symbolizing Compound Statements

Symbolizing a compound statement means isolating its simple components, assigning a letter to each, choosing the connective the English actually asserts, and placing parentheses so one connective is plainly the main one.

Five sentences. The picnic happens unless it rains: unless names the condition under which the first part fails, giving tilde R horseshoe P. You pass only if you submit: only if marks what follows it as the necessary condition, so the arrow runs from passing to submitting — P horseshoe S. Neither the bridge nor the tunnel is open: both are denied, so tilde B dot tilde T. If the alarm sounds then if the door opens the guard responds: the second conditional sits inside the first — A horseshoe, open bracket, D horseshoe G, close bracket. Last: he studies and he passes or he retakes it. Without brackets that has two readings, so the intended one must be marked — S dot, open bracket, P wedge R, close bracket. Name the main connective each time as the check.