Tweak the trace sampling decision docs (#28)

Author: Emmanuel T Odeke

trace/Sampling.md

@@ -1,35 +1,35 @@
 # Sampling
 
-This document is about the sampling bit, sampling decision, samplers and how and when does 
-OpenCensus sample traces. A sampled traces is a traces that gets exported via the configured
+This document is about the sampling bit, sampling decision, samplers and how and when
+OpenCensus samples traces. A sampled trace is one that gets exported via the configured
 exporters.
 
 ## Sampling Bit (propagated via TraceOptions)
 
-Sampling bit is always set only at the start of a Span, and is using a `Sampler`
+The Sampling bit is always set only at the start of a Span, using a `Sampler`
 
 ### What kind of samplers does OpenCensus support?
-* `AlwaysSample` - sampler that always makes a "yes" decision every time.
-* `NeverSample` - sampler that always makes a "no" decision every time.
+* `AlwaysSample` - sampler that makes a "yes" decision every time.
+* `NeverSample` - sampler that makes a "no" decision every time.
 * `Probability` - sampler that tries to uniformly sample traces with a given probability. When 
-applied to a child `Span` of a **sampled** parent `Span` then it keeps the sampling decision.
+applied to a child `Span` of a **sampled** parent `Span`, the child `Span` keeps the sampling decision.
 
 ### How can users control the Sampler that is used for sampling?
-There are 2 ways to control the `Sampler` used when the library does sampling:
+There are 2 ways to control the `Sampler` used when the library samples:
 * Controlling the global default `Sampler` via [TraceConfig](https://github.com/census-instrumentation/opencensus-specs/blob/master/trace/TraceConfig.md).
-* Pass a specific `Sampler` when start the [Span](https://github.com/census-instrumentation/opencensus-specs/blob/master/trace/Span.md)
+* Pass a specific `Sampler` when starting the [Span](https://github.com/census-instrumentation/opencensus-specs/blob/master/trace/Span.md)
 (a.k.a. "span-scoped").
   * For example `AlwaysSample` and `NeverSample` can be used to implement request-specific 
   decisions such as those based on http paths.
 
 ### When does OpenCensus sample traces?
-The OpenCensus library does sampling based on the following rules:
-1. If the span is a root `Span` then a `Sampler` will be used to make the sampling decision:
+The OpenCensus library samples based on the following rules:
+1. If the span is a root `Span`, then a `Sampler` will be used to make the sampling decision:
    * If a "span-scoped" `Sampler` is provided, use it to determine the sampling decision.
    * Else use the global default `Sampler` to determine the sampling decision.
 2. If the span is a child of a remote `Span` the sampling decision will be:
    * If a "span-scoped" `Sampler` is provided, use it to determine the sampling decision.
    * Else use the global default `Sampler` to determine the sampling decision.
-2. If the span is a child of a local `Span` the sampling decision will be:
+3. If the span is a child of a local `Span` the sampling decision will be:
    * If a "span-scoped" `Sampler` is provided, use it to determine the sampling decision.
-   * Else keep the sampling from the parent.
+   * Else keep the sampling decision from the parent.