diff --git a/ch05/loadbalancing/echo/go/client/main.go b/ch05/loadbalancing/echo/go/client/main.go
index 2fc30fd..6eb9ab7 100644
--- a/ch05/loadbalancing/echo/go/client/main.go
+++ b/ch05/loadbalancing/echo/go/client/main.go
@@ -68,7 +68,7 @@ func main() {
 
 type exampleResolverBuilder struct{}
 
-func (*exampleResolverBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
+func (*exampleResolverBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOptions) (resolver.Resolver, error) {
 	r := &exampleResolver{
 		target: target,
 		cc:     cc,
@@ -95,7 +95,7 @@ func (r *exampleResolver) start() {
 	}
 	r.cc.UpdateState(resolver.State{Addresses: addrs})
 }
-func (*exampleResolver) ResolveNow(o resolver.ResolveNowOption) {}
+func (*exampleResolver) ResolveNow(o resolver.ResolveNowOptions) {}
 func (*exampleResolver) Close()                                 {}
 
 func init() {
diff --git a/ch05/loadbalancing/echo/go/server/main.go b/ch05/loadbalancing/echo/go/server/main.go
index ec45d7d..1343494 100644
--- a/ch05/loadbalancing/echo/go/server/main.go
+++ b/ch05/loadbalancing/echo/go/server/main.go
@@ -18,6 +18,7 @@ var (
 )
 
 type ecServer struct {
+	ecpb.UnimplementedEchoServer
 	addr string
 }
 
@@ -57,4 +58,4 @@ func main() {
 		}(addr)
 	}
 	wg.Wait()
-}
\ No newline at end of file
+}