在尝试将RevMob横幅广告和全屏广告应用到我的应用中时，我遇到了这些错误。我该怎么办？
Undefined symbols for architecture armv7s:
"_SCNetworkReachabilityGetFlags", referenced from:
-[BCFAdsReachability connectionRequired] in RevMobAds(BCFAdsReachability.o)
-[BCFAdsReachability currentReachabilityStatus] in RevMobAds(BCFAdsReachability.o)
"_SCNetworkReachabilityCreateWithAddress", referenced from:
+[BCFAdsReachability reachabilityWithAddress:] in RevMobAds(BCFAdsReachability.o)
"_SCNetworkReachabilityCreateWithName", referenced from:
+[BCFAdsReachability reachabilityWithHostName:] in RevMobAds(BCFAdsReachability.o)
"_SCNetworkReachabilityScheduleWithRunLoop", referenced from:
-[BCFAdsReachability startNotifier] in RevMobAds(BCFAdsReachability.o)
"_SCNetworkReachabilityUnscheduleFromRunLoop", referenced from:
-[BCFAdsReachability stopNotifier] in RevMobAds(BCFAdsReachability.o)
"_SCNetworkReachabilitySetCallback", referenced from:
-[BCFAdsReachability startNotifier] in RevMobAds(BCFAdsReachability.o)
ld: symbol(s) not found for architecture armv7s
clang: error: linker command failed with exit code 1 (use -v to see invocation)