```java
public class MainActivity extends Activity {

    ImageView maru_button,batsu_button,qbutton,rbutton;
    private SoundPool mSoundPool;
    private int maru_SoundId,batsu_SoundId,q_SoundId,r_SoundId;

	InterstitialAd mInterstitialAd;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        maru_button = (ImageView) findViewById(R.id.maru);
        batsu_button = (ImageView) findViewById(R.id.batsu);
        qbutton = (ImageView) findViewById(R.id.qbutton);
        rbutton = (ImageView) findViewById(R.id.rbutton);

        maru_button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //音声
				if (mInterstitialAd.isLoaded()) {
					mInterstitialAd.show();
				} else {
					mSoundPool.play(maru_SoundId, 1.0F, 1.0F, 0, 0, 1.0F);
				}
            }
        });

        batsu_button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mSoundPool.play(batsu_SoundId, 1.0F, 1.0F, 0, 0, 1.0F);
            }
        });

        qbutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mSoundPool.play(q_SoundId, 1.0F, 1.0F, 0, 0, 1.0F);
            }
        });

        rbutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mSoundPool.play(r_SoundId, 1.0F, 1.0F, 0, 0, 1.0F);
            }
        });

        AdView mAdView = (AdView) findViewById(R.id.adView);
        AdRequest adRequest = new AdRequest.Builder().build();
        mAdView.loadAd(adRequest);

		mInterstitialAd = new InterstitialAd(this);
		mInterstitialAd.setAdUnitId("ca-app-pub-3940256099942544/1033173712");

		mInterstitialAd.setAdListener(new AdListener() {
			@Override
			public void onAdClosed() {
				requestNewInterstitial();
			}
		});

		requestNewInterstitial();

    }


	private void requestNewInterstitial() {
		AdRequest adRequest = new AdRequest.Builder()
				.addTestDevice("SEE_YOUR_LOGCAT_TO_GET_YOUR_DEVICE_ID")
				.build();

		mInterstitialAd.loadAd(adRequest);
	}

    @Override
    protected void onResume() {
        super.onResume();
        //音声
        mSoundPool = new SoundPool(4, AudioManager.STREAM_MUSIC, 0);
        maru_SoundId = mSoundPool.load(getApplicationContext(), R.raw.correct, 0);
        batsu_SoundId = mSoundPool.load(getApplicationContext(),R.raw.wrong,0);
        q_SoundId = mSoundPool.load(getApplicationContext(),R.raw.question,0);
        r_SoundId = mSoundPool.load(getApplicationContext(),R.raw.result,0);
    }

    @Override
    protected void onPause() {
        super.onPause();
        // リリース
        mSoundPool.release();
    }
}
```