I know what to do,provided thatnobody asks me. Here the underlined part is a/an -

• I know what to do, provided that nobody asks me. Here the underlined part is a - Conjunctional phrase
• Conjunctional phrase:
- A conjunctional phrase conducts the function of the conjunction.
- কোনো phrase বা শব্দ সমষ্টি যখন conjunction এর কাজ করে তখন তাকে Conjunctional phrase বলে।
-  as much as, as long as, as soon as, as well as, along with, together with, either-or, neither-nor, not only- but also, provided that ইত্যাদি Conjunctional phrase.