Which of the following players was once two time French Open Champion A: Michael Chang. B: Pete Sampras. C: Sergei Brugera. D: Jacob Hasic.

Putin has been seen as trying to choose between Medvedev, a business friendly lawyer and Sergei Ivanov, another first deputy premier who built up a stern andhawkishreputation while defense minister. A: warlike B: peaceful C: merciful D: merciless

文献：Guiding of terawatt laser pulses in preformed plasma channels. Nikitin, Sergei Petrovich (Univ. of Maryland, College Park, MD, USA). 160 pp. Avail. UMI, Order No. DA9925820 From: Diss. Abstr. Int., B 1999, 60(4), 1682 (English) 1999.以下说明正确的是：