(a)Form and Admissibility. In all trials the testimony of witnesses shall be taken orally in open court, or such other place as the judge may in his discretion determine, unless otherwise provided by these rules. All evidence shall be admitted which is admissible under the statutes of this Commonwealth or under the rules of evidence applied in this Commonwealth. The competency of a witness to testify shall be determined in like manner. (b) Scope and Examination and Cross-Examination. A party may interrogate any unwilling or hostile witness by leading questions. A party may call an adverse party and interrogate him by leading questions and contradict and impeach him in all respects as if he had been called by the adverse party, except by evidence of bad character, and the witness thus called may be contradicted and impeached by or on behalf of the adverse party also, and may be cross examined by the adverse party only upon the subject matter of his examination in chief. Any other witness may be cross-examined without regard to the scope of his testimony on direct, subject only to the trial judge's sound discretion. (c)Record of Excluded Evidence. If an objection to a question propounded to a witness is sustained by the court, the examining attorney may make a specific offer of what he expects to prove by the answer of the witness, except that the court, when there is a stenographer appointed or when a stenographer has been appointed, upon request shall take and report evidence in full, unless it clearly appears that the evidence is not admissible on any ground or that the witness is privileged. (d) Affirmation in Lieu of Oath. Whenever under these rules an oath is required to be taken, a solemn affirmation under the penalties of perjury may be accepted in lieu thereof. (e) Evidence on Motions. When a motion is based on facts not appearing of record the court may hear the matter on affidavits presented by the respective parties, but the court may direct that the matter be heard wholly or partly on oral testimony or depositions. (f)Interpreters. The court may appoint an interpreter of its own selection and may fix his reasonable compensation. The compensation shall be paid out of funds provided by law or by one or more of the parties as the court may direct, and may be taxed ultimately as costs, in the discretion of the court. (g)Examination of Witnesses. Unless otherwise permitted by the court, the examination and cross examination of any witness shall be conducted by one attorney only for each party. The attorney shall stand while so examining or cross-examining unless the court otherwise permits.