如图,直线\(l_{1}/\!/l_{2}\),\(⊙O\)与\(l_{1}\)和\(l_{2}\)分别相切于点\(A\)和点\(B.\)直线\(MN\)与\(l_{1}\)相交于\(M\);与\(l_{2}\)相交于\(N\),\(⊙O\)的半径为\(1\),\(∠1=60^{\circ}\),直线\(MN\)从如图位置向右平移,下列结论
\(①l_{1}\)和\(l_{2}\)的距离为\(2\) \(②MN= \dfrac {4 \sqrt {3}}{3}\) \(③\)当直线\(MN\)与\(⊙O\)相切时,\(∠MON=90^{\circ}\)
\(④\)当\(AM+BN= \dfrac {4 \sqrt {3}}{3}\)时,直线\(MN\)与\(⊙O\)相切\(.\)正确的个数是\((\) \()\)