设等比数列$\left\{a_n\right\}$的公比$q=2$，前$n$项和为$S_n$，则$\frac{S_4}{a_2}$的值为（   ）

电能表是用来测____的仪表，如图是小军家月初和月末电能表的示数，则他家本月用电____kW•h．

根据所提供的信息, 选择正确的答案。

Piano Player Wanted

Boys and girls, are you music fans? Can you sing or dance? Can you play the piano?

Welcome to our Sky Rock Band.

Please call Victor at 6891-3453 or give an email to music@yahoo. com.

                                                                                    Let's Learn Japanese

Can you speak Japanese? Do you want to learn Japanese? Come to the Japanese club（俱乐部）now.

Time: 9:00 a. m. -11:30 a. m. (from Monday to Friday)

Call Henry at 6543-1248.

Ping-pong Club

Do you like to play ping-pong? Do you want to play ping-pong well? Mr. Chen can teach you. You can come here every Friday afternoon.

Tel: 8623-1940

Add: Room 102 in School’s P. E. Building.

                                                                                                Wanted

Can you swim? Do you like children? Can you help them with swimming on weekends? Come here!

Call Jane at 8330-9785 for more information (信息).

放在水平桌面上的水杯，水杯对桌面有压力，下列说法正确的是（　　）